Unpopular opinion: PK and WM are fine, everything else is just bad and heres why
PK, EVA, WM and even Spitfire are Generic FPS weapons that have very common feel and stats.
Meanwhile for example Assault Rifles have stripped clip sizes and scopes, increased recoil and spread, i belive its purpose was for upgrade system but that made them weak and requires 3rd party items to make them somewhat effective.
But PK, EVA, and WM are not affected by lack of scope, recoil is not an issue and have decent damage and clip sizes out of the box, thats why those are only weapons you want to pick first.
So there are two options to fix this issue:
1: Yes nerf, WM, EVA and PK, both clip sizes and RoF (heavely) and add attachmets that increases stats of both. Those are right now the only weapons that make you feel comfortable in early game.
2: Buff everything else, 18 ammo assault rifle feels just stupid and it takes time to get used that you dont have enough damage in your clip to take down single man with white shield, and you never want anything else but PK or WM in the begining.