Eny has zero impact - plenty of good stuff still available with a 29 eny - which is where it's capped, iirc.
Maybe adjust the ENY of troop carriers to (literally) slow down the horde.
M-3 48mph; SdKfz 251 33mph; LVT(A)2 24mph.
All are currently ENY = 40.
If M-3 ENY = 16; SdKfz 251 ENY = 22; LVT(A)2 ENY = 26.
population ENY troop carrier
16 9 6 15.8 all available
16 7 6 16.2 251 and LVT available
19 7 6 22.4 LVT available
24 9 6 29.0 fly a goon