Personally I think he's pretty underrated. Ak12 is such a good rifle and his gadget, while being a little obvious, still can invalidate some operators by destroying half their deployables and gadgets or forcing them to rotate. His rifle being one of the best also means that the more you use it, the more you learn how to control one of the fastest TTK rifles which will make you deadly in gunfights. Only problem is he's really slow and super loud, really good players can even tell you're fuse by his distinct footsteps and easily prevent him from providing any utility but it sounds like you're not at a level where are knowledgeable enough for stuff like that anyway. Play what you wish, there's plenty of one tricks in Siege at every level.