So I was reviewing vehicle stats for some tactics stuff I'm creating for my IG, and I couldn't help but notice that almost all of the vehicles designated "SPG" for Russia aren't actually capable of indirect fire. Your definition of SPG fits that of self propelled howitzers or artillery. The only vehicles capable of indirect fire within Russia right now are the Su-1-12 and Su-76. The Su-152 and Kv-2 were designed with the intent of being mobile pill-box busters, but they can only provide direct fire, neither even having the capability to elevate their barrels enough for this to be possible. The Su-85 was never designed to be an artillery piece or bunker buster, just a pure tank destroyer. The same can be said for other nations as well. The Type 93 is an AT gun, and its calibre is too small for indirect fire support, and the Semoventes (although the 75/90 was given out to divisional artillery) and L3 are the same concept as the StuG, which isn't an SPG rules wise. I'm sure there is a reason for the stats being this way, and at the end of the day it is just a game, but I feel like as historical enthusiasts, we should at least try to represent these vehicles accurately within the game. (I hope that didn't sound too rant-y, that wasn't the point)

I realize that by removing the SPG rules for these units can hamper the performance of an army, so I have some suggestions:

For Russia:
203mm Howitzer M1931(B-4) "Stalin's Sledgehammer": This is already has a model and instructions available, literally all it needs are "official" stats. I see high AP with low DP and MP and moderately-high RP cost
BM-13 Katyusha: Needs a model, but the GAZ AAA already exists for a good base. I see low AP and DP with high MP and low RP cost

For France: (France seriously needs at least one)
Canon de 194 mle GPF: Basically Daldier's Sledgehammer (not funny joke), a big gun on an outdated tractor. I see high AP with low DP and MP and moderately-high RP cost

For Japan:
Ho-Ni I/II/III: Mid-range stat wise in terms of SPGs, more enclosed fighting compartment for higher DP

For Italy:
Semovente da 149/40: Only one built, but it's all Italy's got. High AP, low DP and MP, and moderately-high RP cost

These additions would give every current nation at least one functional SPG, and some could be quite powerful! (Also more vehicles, which is equal hype!)