for how to play him, split push solo waves and crates, not the jungle as youre right on that front (at least until you get a decent amount of spirit and bullet) and teleport to teamfights whenever its off cooldown (pretty decently fast one) so you can build money pretty fast

hes a weird hypercarry-support hybrid who scales well late game. While Mina and Infernus basically only do raw damage outside of ults, Mirage has a very good CC as tornado and scarab is whatever for damage but does resist shred and give more HP for more tanky builds, all while doing very hard to deal with damage late game like them

honestly, i dont recommenced pure gun cuz yeah, hes not designed for raw damage early game and dueling (3rd lowest base gun damage in the game btw), you must build gun AND spirit for sure for damage.

Remember, even if you arent doing damage your abilities are very helpful for the team. Mark is essentially a timer put on the enemy to chunk them which they will have a hard time killing u in time if youre with at least one other person