That’s the inherent issue with best weapons in the game. They get used a lot since they are that good.
It is very difficult to design weapons for games if the intent is that players won’t use one specific set of weapons the most.
You could make all weapons perform the same, so there won’t be any actual advantage over one or another. But that leads to the issue of weapons being copies of each other, where only the appearance is different.
Another option is to limit available weapons but that too has it’s issues, leading into lack of variety, if you only have 2-4 weapons to use.
In the end, i think the weapon usage comes down for players to decide, rather than devs to limit it for the players.
For example, 6* Kpist is better in DPS and mag size than 5* HP5 but i prefer to use 5* HP5 instead. And when i face harvs/tanks, i prefer to chip away their HP with my 6* AG4, rather than blowing them up with 6* .50 cal with only few rounds.