SU sniper stragety question

I play mainly 2v2.

In some maps, I will use sniper against WM.
usually, I go sniper>con>con>con>AT nade>m5AA with NKVD.
The only problem is that when the wm go sniper, I have to seize fire.
Then the situation becomes difficult. I have to use 3con go against mg42+2gren.
I try to use M3 to reveal the sniper or simply threaten the enemy sniper to go back so my sniper can have a couple of shots. but once WM has pack gun, there is nothing I can do. M5 or t70 can't break the line and P4 is coming soon. WM with 222 spotting scope just pushes with MG and AT gun destroying my sandbag.

so I am here looking for some suggestions. correct me if I play wrong.

I’m not a fan of sniper start. It usually works a lot better when you get it after 5mins when you have an army to support it.

2v2 player here as well, I have been through similar thought process as you, using my sniper to bleed MP and force enemy MG to leave. A lot of 2v2 maps are narrow, which makes MG effective at holding ground. Most common ways to force MG off as SOV is via a sniper, mortar, zis gun and vehicles. I will now explain how and when to use which:
- mortar is only good when the enemy has 1xMG, if the enemy has more than 1 MG on his side, you can't smoke or barrage them both quickly enough. SOV mortar is generally a good investment vs OST due to the flare which gives you vision and allows to make the right plays. Mortar also works well vs MG in garrison.
- zis gun can barrage with the HE shells landing rapidly around the target and this will most likely force the mg to retreat, it's recommended that you first send sweeper-CE to draw MG fire, start the barrage and lead an assault if you are trying to recover lost territory. Just don't start the combat with zis barrage or the enemy might react too early and reposition too quickly. First get some tax on enemy micro, then hit him with indirect fire.
- as a gimmick you can also try attacking enemy MG with a Maxim. Maxim continues to fire long bursts even if pinned, it also has longer firing range than infantry. Once axis MG is suppressed or pinned, it hardly does its work. I find it hillarious, only use this if both your and enemy MG are in equal cover.
- M3 with flamer is especially useful if the map is open enough to allow to attack where the enemy is not present. If you can redirect enemy infantry to react and move to a different location where you attacked, some axis players leave MG to protect the other position. Lone MG is very vulnerable to M3 attacks. If you catch the enemy MG in a building you have a good chance to wipe it on retreat and potentially steal it.
- sniper WM has a lot of methods to counter the sniper play: sprinting stormtroopers while in camo (to kill sniper), 222 suicidal push, upgrading regular troops and MG with doctrinal camo, using smoke bombs recon (cheap) + OST sniper for countersnipe. In 2v2 before you decide to go sniper I highly recommend to check the doctrines of the opponents. If OST player has recon plane / smoke bombs, camo or stromtroopers it will be significantly easier for him to kill your sniper than for you to kill his. Additionally, by going sniper first you risk facing Assgren OST player and you risk being pushed off the field from the start. It is more difficult to re-take the territory than to hold it, this is why I don't recommend building sniper as the 1st unit in 2v2 (or other slow start), even though I like playing sniper a lot. If you really want to play sniper, make sure your doctrine has recon plane, using it you can reveal or check for enemy sniper and he has to either retreat or risk being shot (if he doesn't know the position of your sniper). SOV recon planes are CP4 which means that you can only be safe using sniper from CP4 onwards. In the early game you can use Radio intercept, however knowledge of enemy vehicle/sniper presence doesn't necessarily help you deal with it later. Additionally there is no SOV doctrine to have both radio intercept and recon plane so while you are more or less informed with radio in the early game, you are vulnerable once the enemy builds his sniper, opposite is true for the recon plane ability.

My tip of the day for you is to use the soviet advantage over WM of not having to build any building at the beginning of the match. In 2v2 just take your CE and build cons and 90% of the time grab your fuel point (or adequate) and get cons behind green cover, once you're there. You will be there before WM (unless he uses call in inf). You will be fighting for at least 10 minutes for that point over and over. It's good to have it while the fight continues. Enemy can't just stand in the open of the capping point in the middle of a firefight, because his models will die quickly without cover. You can connect this point using your next squads being built, while they are on their way to the frontline. Recently I've been playing with 3xCons and 2xCE (flamer + sweeper later). CE with a flamer is an excellent choice when you use conscripts because of the merge ability allowing CE to stay on the frontline and deny the enemy cover/buildings for longer.
Later you can decide which tier you think you should go. You can build a sniper and have AA HT to protect it from 222 and also to suppress any charging infantry. Cons with the new, cheaper AT nade cost and sprint are also a good choice to protect your sniper from enemy vehicles. You will most likely play your inf like shit as they will be outnumbered because you sunk a huge chunk of MP into T1 and a sniper so cons will be just as useful as penals for being punching bags. You just want to drag engagement for your sniper to bleed the enemy. In the past WM had less MP available to it than it has now due to the lowered T2 cost. In the past you could potentially bleed OST enough for it not to have resources to buy early 222 or flame HT with good infantry roster. With the lowered OST T2 cost performing early bleed with a sniper to this level of harm is no longer possible I think.

T2 is often very useful and I highly recommend having at least 1 zis gun, so I don't often find it worth to build T1 and a sniper. I usually just go T2 to T3 and get myself a T70 or sth. A well played vehicle can give you similar benefits as a well played sniper but is less risky and doesn't sacrifice early map control. Use your vetos well, ban maps you don't enjoy and rails and metal for being narrow and crossing in the woods for being too small for 2v2. On both of these maps you can close entire side with just 1 MG with very limited attack options.

If you want to play sniper like there is nothing else in the world, you can play it as Brits vs OST or OST vs USF. Brits commando commander is pretty good with the occasional recon plane and camo infantry to ambush enemy sniper and air supremacy to bully OKW. Other commanders with command vehicle are also very good because it's CP2 ability that allows you to send out a recon plane circling around the vehicle (50MU). You can use it to check for or reveal the enemy sniper. Also the AEC is a great counter to 222 that could harm your sniper as Tommies don't have snares. You also have no additional tech cost for the sniper. It's in the main tech route.

TL;DR play on good maps, reach your fuel first, don't let go.

2v2 player here as well, I have been through similar thought process as you, using my sniper to bleed MP and force enemy MG to leave. A lot of 2v2 maps are narrow, which makes MG effective at holding ground. Most common ways to force MG off as SOV is via a sniper, mortar, zis gun and vehicles. I will now explain how and when to use which:.........

Thanks for your guiding. it helps a lot.
3xcon 2en is a good build as you said. I use it too.
Also, when I saw any ambush tactic, stormtrooper, and assgren doctrine I will not go sniper.
The suggestion about 3con to hold the land and tech for sniper and light vehicle is cool.
it is true that with radio intercept I can only seize fire which limits my utility of my sniper.
so I always struggle once enemy sniper out.