Awesome, I've watched plenty of your 2.301 Replays. CoH2 really needs some fresh competent 1v1 players. Gonna watch the replay and give some advice.
Okay here we go:
1. When you put an MG in a house you can manually face it towards one side of the building. In this game sometimes your MG was facing towards the bushes which obviously doesn't make any sense because it needs to reposition first before it starts firing. You can see the firing arc by clicking on the house. If you're using the Classic Hotkeys it's "A" and then click in the direction the MG is supposed to face. If you do this the MG is "locked" into that direction so it won't automatically switch windows anymore if there's an attack from another side. So after doing it you should switch back to automatic repositioning which is hotkey "S".
2. You used attack vehicles only on your P4 even though there were no enemy vehicles on the field. It's one of the biggest improvements compared to CoH1 and should always be used during Tank fights. (No more M10s wasting their shots at infantry etc
3. You should always upgrade your Grenadiers with LMG42s if you have spare munitions. They're really good unlike in CoH1 and are pretty much considered a no brainer upgrade unless you use a doctrine that has G43. LMGs in this game are best used at long range.
4. Against USF it's recommendable to go T2 unless you pull off an early cut off move. Against good players you will need an AT-Gun and possibly a Scout Car. Instant T3 can work against Captain play (as it did in this game) but against a quick Lieutenant it will fall apart due to the strength of the M20. Brits and Soviets don't have the light vehicle power of the USF so T1-T3 is much better against those.
5. I would always build at least 3 Grens against USF because they have Panzerfausts which cause a guaranteed engine damage (similar to stickies in CoH1) if the vehicle gets below 75% health which is essential against light Vehicle play.
6. When playing competetively I wouldn't build the Sturmofficer. It's not terrible but there are better ways to invest your manpower. (another Gren, Panzergrenadier, Mortar, a different doctrine unit etc)
I may have forgotten something but that's it for now.
Btw, as you've probably already noticed the replay section isn't as active as it used to be on GR, people mostly watch streams instead. If you want more advice just post another replay I will check it out.