There's also no ballistic upgrade (MG 42, BAR, G43, DP, etc) that reduces DPS. All of them increase DPS at all ranges, even if it's negligible, but you won't be hurting if your MG Grens are up close, or G43 Grens at range. Conscript PPSh is the black sheep, it doesn't have this benefit.
Yes, there are such upgrades in the game, that doesn't have downsideы, I have complicated feelings about them. I'm ok with upgrades that have drawbacks, but they should be much cheaper than no-brain upgrades and more potent in their specialization role. Personally I would like to see some close DPS buff for conscripts or even 6 PPSH, to make them deal 55.2/10.2/1.2, it will have DPS like full squad of asgrens with MP40 - 56/10/1.5, ans still be less than 4 STGs. Or give them give them extra ability with upgrade - grenade, focus fire, and etc.