https://www.coh2.org/replay/55187/1v1-usfvsohkharkov
so Ill TRY to not repeat what he said. Ill just mention key things i thought you did wrong.
1. Building counterproductive sandbags
If your sandbags are built like this they can be used by your enemy as well as you. If you're gonna build them make sure you build them in a way that only you can use them, or wire off the side that your enemy would use.
2. Threw your stuart
You shouldve used your FIRST stuart to push your enemies fuel, rather than pushing up right in front of his base. You end up losing your stuart and not accomplishing much with it even though there was a very clear opening for almost the entire early and mid game for you to take his fuel and cutoff with your mortar and stuart and force him to react as such.
3. Rebuilding a thrown stuart
Is almost never a good idea vs someone that is using a tiger/callin doctrine unless you're very confident in your ability. 2 stuarts is 140 fuel. You proooobably should tech instead of continuing to build stuarts.
4. CLOSE THE GAME
You have him down to about 230 vps about 11 mins in. You do alot of pussyfooting with your force instead of attacking his main income source(his fuel, munitions and cutoff)
As usf you should never have huge lulls where you're not attacking. Attack. Poke. Prod. Flank. Smoke. Etc. Your opponent always has a weak opening somewhere this early in the game. pock and prod until you find it.
In this case it was his west flank, as I said before you didnt really push there for some reason. Why
ignore that? push it!!
5. Double stuart hurts sometimes
Because again you didnt push where you probably should have. You left his fuel uncontested despite investing into double stuarts, so he ended up getting a panzer 4 before you had any medium armor yourself.
TLDR
If youre gonna invest into 2 light vehicles like that you must harass your opponent so badly that he doesnt get any resources for medium armor before you. You not harassing, in addition to your overinvestment and 'pussyfooting' with your light vehicles resulted in a comeback opportunity for the ostheer player.
Other than that you do play decently well and youre not 'clueless'. You lack confidence, aggressiveness at times, and expierience based foresight. Just take these tips we're all giving you and work them in, and over time you should be just fine.