Hey dude.
The short answer to your feedback is to just write of this game. You faced a top 200 guy with thousainds of hours more than you under his belt. The odds were completely unfair and you just picked the very short end of the stick in the match making.
Having said that I will still give you some general pointers on your specific questions, but as I am on holiday I will not be able to watch the game so some things will be guesswork.
1. the UC is a serious problem for wehr in the early game. there is really not any other way of putting it frankly. Regardless of your opening and doctrine, you really won't have a good counter to it before the 222, and if managed right you will be so fuel starved that the AEC will hit the field at the same time. I wish I could give you better advice, but in short you will just have to try and cap the other side of the map and perhaps see if you can get lucky with a faust and ganging up on it with a few grens.
2. This problem is most likely tied with the first one. A UK player with good micro of a UC (which a top 200 will have) is going to absolutely punish your fuel.
3. I imagie that your opponent had picked the special weapons commander with the m M3 truck and possibly put in one or two tank hunter Infantry sections. These will outmanouver and outgun your 222. Snares and well placed mines can counter it, but if he took you by surprise then there is, once again, not much you can do.
4. pretty much the same again i suppose
5. AHA. Here I might be able to help you a bit
The bofors and sim city can be a real struggle for newer players to handle. I personally found that the best way to deal with them is to get a doctrine with the mortar halftrack and use incindeary rounds and barrage on them- Two is ideal as you can time it between brace and ensure that they cannot be repaired by neaby infantry as they will die to the flames. There are other options as well, but I found that this is the easiest and requires the lowest maintenance.
I hope this was of some help and would also reccomend that you read my beginners guide if you haven't already.
https://www.coh2.org/guides/70864/from-recruit-to-veteran
Best of luck and keep at it. you will get better in time