i've been saying for years now that multiplayer gun unlock systems are handicapped. either you make some guns straight upgrades which sucks because new players are gonna get richarded by more experienced players with objectively better weapons or you make weapons minimally different which negates the entire point of a level unlock system to begin with. you have to unbalance your game or make guns feel like nothing more than a change of scenery.
2142 did it really well imo, there were a total of 5 different assault rifles:
-Two faction-specific ones for the assault class that performed more or less the same and had 30 bullet mags
-One unlock for the assault with 20 bullets and higher damage and accuracy but worse recoil (a battle rifle, basically)
-Another unlock for the assault that had 40 bullets and better recoil control but worse accuracy
-An unlock for the recon that had 30 bullets and all the lowest stats for the other guns combined which sounds bad on paper but it IS an assault rifle for a class that otherwise only gets sniper rifles, so it's worth taking if you want to go be a saboteur.
you dont need a loving spreadsheet nightmare of different guns, just a core gun and a handful of sidegrades