New long campaign player needs tips.

[Imp]

Hence the SP Mortars Andy suggested

Also as Andy suggested infantry with G Ladung will easily deal with them esp if the AI lets them get out front just pick a suitable spot. As you have good experience even the guys with handgrenades can gang up & kill them as they wont run often. Does not work as the likes of early Russians mind they scatter & run, they do have problems with armour.
The platoon of Pioneers I suggested can also be useful vs armour.
Having the MMGs means you can pinn down his infantry, done correctly you can break down the attack making them easier to deal with & striping the tanks of infantry support.
If need drop a bit of smoke to assist a very powerful tool.

Also as a thought less tanks for you is less tanks for him yours cost much more than his so he will get 3 for every 2 you have roughly