^^
I hope you find my criticism equally warm, and positive. Let’s jump into things.
I liked your attitude early on, pressing high up the map and taking as much ground as quickly as possible was very admirable, but also caused you some problems.
Strategically, attempting to spread out, create space, and overwhelm a Wehrmacht player is always a good idea, but tactically, I think you tried to do much without enough resources.
Realistically, I think you were lucky not to lose your first two rifle sections from overextending them, as they were left without support, usually engaging in 1 on 2 (or more situations). This was endemic throughout the first 10 minutes where you did not win a single engagement or force your opponent from the field until a little after the 9th minute when you attacked your opponents fuel point in force. Until that point, each battle you fought was not accomplishing anything much except bleeding your own resources. I think the root cause of these struggles came from an incongruence in your tactical execution and how you spent your manpower.
By requisitioning the Captain before a fourth rifle squad you were left outnumbered and out manoeuvred which spoiled your main advantage as the USF. This also delayed both your triage and your M5A1. May I suggest in the future either, if you wish to keep trying to traditionally swarm and outflank your opponent requisitioning a fourth rifle section before your Captain to maintain your field presence. Or, if you wish to maintain a smaller core army, perhaps you could try scaling back and locking down your opponent in a siege by staying more compact and utilizing your mortar, or even bringing up another one to barrage your opponent and force them to attack you. Either way, point being, you did not have the resources to maintain your presence on the field or effectively execute your tactics.
It was also disappointing to see the M5A1 brew up as it did. As your only effective counter to the sniper and the only tool you had to reclaim some of your early loses accrued, losing it as you did was a sort of final nail. Be mindful about infantry units with snares, don’t be afraid to attack move and keep your distance, and although that rear armour hit can be tempting, remember that each unit is precious and it is not worth “trading”. Keeping your units alive should always be top priority over inflicting damage.
So to surmise, try and be more mindful with your economy, keeping your tech timings tight. Also try and be a bit more conservative with your troops. Analyse the tactical scenario and do not fight unless you (without overestimation) have a realistic opportunity to win the day. Search for engagements you can win, however small, and eventually the battle will be yours.
To answer your specific questions regarding sieging buildings, approach sides with few windows. The less guns firing at you the better, flame weapons are always effective (unless it’s stone) bringing indirect fire can also be useful. Also when using grenades, try and predict how your opponent behaves. If they are like rabbits and jump out at the first sign of danger, try throwing the grenade at the doorway, so your grenade lands at the feet of the evading squad, or if they stick in the structure, try to throw the grenade at the windows. The AOE effect will cause greater damage to the actual squad members instead of the structure.
I hope you find this useful, there really was not too, too much you did wrong, but often against equal opponents small mistakes may cost games. Keep playing, I’m sure you have a great future ahead.