They are supposed to be alternative, not complete replacement.
They are not?
Alternative is not the same as replacement.
What is alternative? In standart game you rarely go for more then 4 squads of mainline, even going 5 can be considered too much. So you cant start with standart 4 volks build and later throw PFs because there is no point in doing so.
You objectively dont want to mix them with volks, because they are very weak early on. You dont want to replace volks with them in smaller gamemodes.
In this picture you really want to maybe just have 1 sqaud of them to either use flares or give them schrecks, not G43 because you missed the time to vet them and obersts arent too far away by that point.
Considering this, its not an alternative squad then, its a highly specific squad which you wont use more then 1 or 2, then why balance them as an alternative to volks begin with?
Good example of Alternative are ass.grens and assault sections. You either can mix them with standart mainline or you can play only with them, both ways works, both ways have advantages\disadvatages.
To tone them down from team games, where they are as overpowered and oppressive as penals used to be before people learned how to actually fight them.
The unit has a very clear role.
Now it needs to be polished to fit that role without completely stealing it from volks.
Well they took weapon slot from them, alright. This fixes absolutely nothing, because in teamgames PFs G43 blobs are OP af and not because they had one weapon slot and in smaller gamemodes they are still pointless. This is my exact point, that this balance flips are for nothing and solves nothing.
You either should make them into a proper replacement and balance upgrades\stats\abilities according to that or if you dont want them to be a replacement, then they should be made into something more appilling as a supporting\additional unit.