Actually I redid your cavalry to the more useful dismounted variety with cavalry mounts to ride into battle, so you should be in more battles soon
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I need volunteers for some more positions:
Desant team (for T-34s)
PTRD platoon
Tank hunters (AT mines) platoon
PTRS platoon
85mm anti-tank gun platoon
T-50 tank platoon
Mechanized scout section
If you don't know what a desant team is they are the solders with PPSh's riding into battle on tanks: