A few tips would be great

Ok, I'm by no means a great player but here is what I noticed... writing this as I watch the replay, so maybe a bit out of order.

Start: Use the second pio to build the T1 building, not the first one. You could be out capping and the building can't produce anything yet. If you use the second pio, you'll finish the building often around 230-250 manpower, so you don't lose time and have your first sectors earlier.

You can save a bit time by moving the flag of buildings so your units spawn from the other one of the two spawn points.

Why the third pio? It really doesn't offer you anything. You could get a Grenadier or so instead.

After your halftrack comes out you float a lot of manpower. You could get Panzergrenadiers and a Pak at this point because Soviets with a T2 start often go early T3 for a T70.

Doctrine choice... why do you commit so early to it when you can't yet use anything from it?

By the time his T70 spawns you have no AT (Panzerschrecks, Pak). Your're researching T3 and have the fuel for a P4 but it is really risky. You're also floating over 1000 manpower that you could use for something, even if it is just a cache.
You also have only 1 grenadier. With two your chances of hitting a Panzerfaust would be a lot better so you could at least stall.

You're pushed off by the T70 but instead of getting some counters out, you take ages to build the T3 building. Even after completing it you're not building a unit from there.

You get a lot of flamers but I think on their own they are too hig of a risk. Pios take more damage than Grenadiers and Panzergrenadiers and if they are under fire their flamer can explode.

You're still floating a lot of manpower and instead of getting infantry you're just replacing your lost pioneer... Even if your plan is to get a howiter as soon as possible, you should have built infantry long ago, especially because using them to fight gets you to 4 CPs faster.

1900 manpower and over 350 munitions float...