For USF my favorite go-to is Rifle Company: Rifle Flare + 2 AT Gun + Screening Troops. Easy spotting and it'll be dead before they realize it unless he has troops nearby.
For Soviets SU-85 sniping with focus sight and/or the buffed ML-20 Howitzer usually works wonders. Otherwise just spam mortar barrage and wear it slowly down.
But yeah, you quickly find out what NOT to do with Tier 4 building after playing as OKW or at least I did lol
