I'm lucky enough to temporarily and mostly be doing this full time. With multiple caveats - taking on freelance projects on the side, having a partner who still works a real job, being older now and joint homeowners after a couple of decades working real jobs - but that's only been the case for the past year or so, it's not what you'd call a stable income, and we're ready to change back at any point when we have to. And that's still relatively speaking an immensely privileged position for any creative writer and especially for anyone who works in audiodrama.
With regards to "I'd make more money doing X or Y" - well, yeah. You can do both, of course, and for the vast majority of writers in any medium that's the practical reality to make ends meet, and there shouldn't be any stigma involved in that. Bukowski worked in the post office until he was almost 50 and he'd been getting published for half his life before that. Plenty of great writers have been on benefits, plenty of great writers have done quasi-creative work commercially in advertising or copywriting or editing to keep themselves afloat financially while utilising their skills.
Do what you have to do, and remember that there's no expiry date on a creative output - you're not an actor trying to get a starring role in Hollywood before your first wrinkle dooms you to obscurity. You're writing about life, and you're probably going to get better at writing about life as you go on living.
When I was younger I think I imagined there was a hard dividing line between being A Real Professional Artist (it's impossibly hard but it'll all pay off once I'm noticed! It'll prove my worth as a human being and make all of the struggle worthwhile!) and a regular person with a regular job that eats away all my time and energy (sellout, giving up on my dreams, never going to write again) and ultimately that's a narcissist's fantasy built on insecurity. Your goal is to make the time and space to write, but when you can't make the time, that doesn't mean you've failed. You can always come back to it.
TLDR: I am writing full-time right now, sort of. It probably won't last. It's OK if it doesn't last, and it's OK not to be making a full-time living out of writing, temporarily or permanently. Don't let it stop you. The kid from Whiplash probably burnt out six months after that last drum solo.