In Borderlands 3, the Companion Gun is a legendary weapon designed for the character FL4K. It can be a decent option depending on your build and playstyle.
FL4K can utilize the Companion Gun effectively due to their ability to increase damage output and benefit from the pet-related skills. If you focus on a build that synergizes well with FL4K's pet abilities, the Companion Gun can complement your damage potential, especially in team gameplay where the gun's abilities can provide additional support.
However, the suitability of the Companion Gun also depends on your overall build, gear, and the type of enemies you are facing. Some players may prefer other weapons that provide higher damage or better fit their specific strategies.
Ultimately, it's best to try out the Companion Gun in your loadout and see how it works with your particular build and playstyle. If you enjoy using it and find it effective, it can be a valuable part of your arsenal.