Soviets are currently fine, perhaps some small buffs for the T-34/76, rest is fine
Still, T4 is not viable. A slight nerf to the SU-76, and a slight buff to the SU-85 would go a long way. SU-85s still get rekt by Jadgpanzer 4s 99% of the time.
As for the T-34/76s, I think a steadier penetration would help. Its penetration is 120/100/80, which leads to a lot of RNG decided situations. Make it the same as the Panzer IV's, 120/110/100.