After the untimely death of my old rig and black friday purchase of the new and better one, the hiatus seems to have messed with my strategic ability (I can't really blame it on the new and much better gaming hardware

I play as the americans but it has been a general pattern for me to be ahead for most of the game only to tilt and throw it all away in the end.
I have made some considerations on what I think I probably did wrong here, but would like some more specific feedback as well if anyone has time:
- I underestimated my opponents grenade dodging ability, which made me burn a lot of valuable munitions.
- I think it was a mistake going for armor commander. The reason I did was to be able to get the flamer and minelaying combo of combat engineers, but the better options would probably have been heavy cav for the mines for riflemen, who could also clear buildings with grenades. I still struggle more with americans because I usually rely a lot on mines for controlling the game.
- I teched for leutenant, but never got any of the t2 units which was a huge waste and mistake in hindsight. I should at least have gotten a 50. cal for crowd control and probably also a utility car, but I was afraid that I might be chased down by a 222 (though he never fielded one)
- I never teched for major, hoping to rely on wolverines in the beginning. That was probably a bad mistake as they don't seem ideal fighting under urban circumstances and the major would have made it possible for me to move my ambulance and retreat point forward which could probably have prevented the tilt.
Now that I have submitted myself to thourough self-criticism I hope one of you might take the time to finish me off and point out the more specific parts of the game where I messed up.
I'm here to learn so no need to mollycoddle me

Thanks in advance!