All versions of the FG 42 in game have their bayonet modled, a similar style of that of the MAS 36’s bayonet, stored under the barrel and clearly visible, just waiting to be used. I think it would be fair to flip these bayonets around and for them to be usable, as all other BR5 select fire rifles have bayonets and it would be quite easy to do.
This can be done in a similar way to the scope on the FG42 sniper. When equipped, it flips down the iron sights, when not equipped, the irons are flipped up. The FG42 bayonet could exist as an item with no physical model, when equipped, it just alters the model’s bayonet to look as if it were extended. Same could be done with all internal bayonets (mas36, for example)
Overall, it’s worth giving weapons without a bayonet some competitive advantages over weapons with a bayonet.
Weapons without a bayonet provide bonuses to weapon swap speed, vehicle entry, and vehicle relocation.
Give weapons without a bayonet the ability to charge without a bayonet, but this charge will end not with a bayonet hit (which they don’t have), but with a knock off the feet.
FG42 with its bipod folded up makes the gun look 4 billion times sexier - I know looks dont matter as much as balance, but if FG42 had its bayonet always deployed … I would cry like a little girl.