On the bright side:
with the new High-Current, low-ripple, long-holdup +12V output, you absolutely can 'just hook car audio to your rig' now.
The neighbors are gonna be pissed.
It's fairly to extremely easy to get 240VAC into your office or bedroom safely, and be 'NEC-compliant'.
For instance: a 20A branch used for floorboard, in-wall, or other electric heating can (to code) have the heaters disconnected and replaced with a single 250VAC-spec 30A NEMA receptacle. As long as there is only 1 receptacle on the 20A branch, and the heaters disconnected, it's both safe, and 'to code' to use a 30A receptacle.
If you are lucky enough to have the outlets in a single room all be off one branch, it would also be safe and 'to code' to replace those outlets with 250VAC NEMA receptacles (wiring and marking them with 'White as Red'). Then, in your breaker box, remove the neutral for that branch from the neutral bar, and connect (and mark) the white to the the other pole on a new 2-pole breaker. (The problem with this install: you cannot use 'normal' 120VAC devices in those outlets any longer. Running a new neutral would allow for having Kitchen-style split-phase or using a multi-voltage outlet.like dryer's do)
The last and arguably 'best' option: Just plop a 30+A 2-pole in your breaker box and run some 3C+Earth (appropriate gauge) thru the attic along the rafters, and down into your office. (There's a few ways, to code, that you can 'bring it down into' the living space)
If you want to make it a legitimate 'home improvement', set up the new run so it's easy to attach an EV charger to the branch (so it can be added before moving). If you're near your garage or outdoor work area/patio, setting it up as a 'welding receptacle' can be handy too (just don't weld using it while any computer equipment is hooked to it)
