That's not a fair comparison because Grenadiers don't even have the option to be bolstered or run around with 2 Machine Guns, no matter how many resources you have you will never get these things. It's the same problem Conscripts have, lacking any weapon upgrades while going up against LMG and StuG troops.
The way I see it is Grenadiers are the gold standard that everything else is balanced around, so maybe Bolstered LMG Sections need toned down and Conscripts need a weapon upgrade, rather than changing Grenadiers in any drastic manner.
Mirror balance would work out nicely.
Give all allies strong T0 MGs, and T0 Mainline inf AT options.
Then give everyone 6 man infantry with 2x LMG upgrades and on-field healing.
Buffing conscripts to be equal to 6x men grenadiers. Giving bolster to everyone, and
MG bunkers to everyone and end-game Panther equivalent (same stats) to everyone.
(And buff everyone's LMGs to be equal to LMG42)
You either want mirrored factions, or you don't.
If that's what you want, don't be shy, go all the way.