1) You need to be familiar with your maps. There is a central cut-off for the south start of Kharkov- which you had crossed over twice by 5:43 and not capped. And you never did cap it, before you surrendered in the 16th minute This meant that all the fuel and ammo points you captured on the South side early on and later were effectively useless, bcs their resources were not streaming back for you. And you were then fighting the Soviets for the said useless capped points, which were yielding you no resources, bcs the central cut-off remained uncapped.In other words you were pretty well fighting with one hand tied behind your back, which was a shame, because you did make some good territorial incursions on both sides. If you review your game again, watch the ammo and fuel gauges, and see how low you were. You effectively had no fuel.
2) Your BO needs revision. Conventional Ost BO is that the starting Pio builds T1 right away, to start Grenadier production - then research 3 or 4 Grens, then MG. In other words, your 2nd Pio was not required at the start. Because you selected a Pio as your second unit, you then found yourself with a Pio capping out front, and as you discovered, Pios without an upgrade or Vet, tend to fare less well against Conscripts than Grenadiers. Essentially, once your first Pio has built T1, you then use it to nab that cut-off and either reinforce somehow eg.wires, or proceed to cap the back points with it
This then forces your lazy Grens to the front
3) If you see your foe has started to mine, you need to think about upgrading your Pio with a minesweeper. You also need to lay mines yourself, provided you have given yourself the upkeep
4) As Rizza said, if you know there is a T34-76 out and about, don't bother researching Scout cars after that - T34s eat them for snacks. (You were placed in that position, because of the failure to cap the central cut off, which denied you your fuel)
5) Consider researching a mortar, rather than several MGs. And MG42s are vulnerable to Conscript Molotovs, unless they are protected
6) As a general rule, try to avoid placing MG42s in buildings, if you know your opponent has selected Molotovs, otherwise they tend to fry, as yours did

(Same rule of thumb applies, if your opponent has researched Penal Squads)
7) I am not a fan of the Commdr you used, but that is highly subjective
tl:dr failure to ever cap your cut-off was a huge self-inflicted wound