Is it possible to change the G43 values only for Panzergrens by reducing the moving DPS and increase long range performance? Giving them a clear role as long range recon infantry would be quite interesting which ostheer currently doesn't have.
It's possible to do whatever you'd want with the G43s, as Panzergrenadiers use their own version of it. Ideally they would give PGrens long range DPS compared to LMG Obers, so they can supersede/supplement Grens in fighting Bren Tommies and double BAR Rifles and the upgrade offers a significant role change compared to the STG44s.
The problem however is that G43s are used by multiple squads and giving one of them a reverse profile of what the other G43 upgrades have (being a low-mid range upgrade) would probably make things very confusing for most players. The G43 sniper upgrade for JLI is already confusing for players, and that one at least has a noticably low rate of fire to help distinguish it.