Oooof I've spent days and weeks as a preteen trying to figure out my hypothetical theme song.
From the plethora of theme songs already in use I'd go with either I walk alone, Metalingus or This fire burns.
But I'd need one of my own if I want to make a name for myself. It would need to be something easily recognizable from the start so I'd probably recommend D4C from ACDC as a template of the type of vibe I'd want
(and then I'd get a 20 second loop like most wrestlers these days with no persona to it

)