Eh, depends how you want to look at it.
6 DPS for any other infantry is quite a lot, but for PGs that's ~10% of their close range dps, but more with range increase, but that is compensated by really incomparably higher on the move DPS especially at longer ranges, so unless you constantly fight on ranges below 20-25 and never have to move in or move at all, g43 outperforms stgs.
If you want to ram rifles into opponent and use it from very close range and approach under cover of smoke or los blockers, stgs will be better.
I've also said its a side grade, but to me, as I have said, what you give up is well worth it vs what you gain, given more mobile nature of PGs, where they utilize g43 form most.
You should specify the range you are talking about since it varies quite a lot.
The moving DPS is about 1-2 DPS higher at close to mid and 5-8 DPS higher at long range. But bear in mind there is no engagement at 35 meters in the game, so you will never gain those 8 DPS advantage over StGs. You realistically get ~5 in the best situations and 1-3 in all others. Standing still for a second at mid range already compensates the lost DPS that you "paid" while closing in.
In an assault, the moving DPS advantage (not moving DPS itself) will not benefit you as much. You're running into enemy positions, but the way the upgrade currently works is to diminish the advantage of itself by doing so.
Your argument also works the other way around: Unless you're constantly moving at range 30+ or chasing retreating squads, the G43s don't have an awful lot going for them.
I think the upgrade would benefit if G43s PGrens got either a clear long range role (however they'd clash with LMG Grens) and/or the abilities were more focused on supporting an assault for other mobile units such as G43 Grens.
Its not weird. It makes your PGs better against pretty much every single type of inf enemy can throw at you. Yes you trade close range DPS, but at the same time your PGs gaining the ability to always engage at their terms.
You want to keep distance against close range squads? You can do it + you have a grende. You want to close in vs long range squads? You can do it. You want to chase someone or push? You can do it.
You are looking at raw DPS and for some reason, you think that huge close range DPS is somehow better, then over-all DPS. Also you shoudnt forget that G43 is a rifle and it has tendency to drop models with few good RNG rolls, unlike StGs.
What I think is weird is that pushing in (which is the point of the G43) is actually hurting your DPS compared to StGs.
You can sprint away from danger, but given the offensive nature of most G43 commanders plus the fact that all other squads that have a sprint come with superior close range DPS (comparison here is twofold, once is G43 vs StG and then close vs long DPS) this makes this ability weird. Sprint on normal PGrens would actually be worth way more than on the G43 version. But sprinting into battle is something you want to generally avoid (flanking MGs etc not included) if you paid for the G43s, otherwise you could have just stayed with StGs.
I am not arguing that there is no niche for G43 PGrens and that the abilities are useless in all scenarios, but that the bundle that the upgrade gets you contradicts its own function to some extend.
The squad should have a clear strength and a clear weakness. They have a clear strength at long range combat, but if their "weakness" is close range, they should not have sprint. Otherwise positioning is not as important.