Advertising is such a tricky one, since the few times I've tried paid ads, they haven't really worked out for me. Twitter was expensive and useless, ComicAds seemed too niche, and while I haven't tried anything on Instagram lately, I'd really rather not make Zuckerburg any richer.
What would be cool would be to approach big comic artists in similar genres to mine for an ad at the bottom of a few of their episodes. That seems to work way better that traditional online advertising.
That, or just throw the money at getting a monster Cintiq and a high-end Mac to power it. I just upgraded to the M1 iPad, which I'm looking forward to using once Procreate patch their app for it, but part of the reason I went with that was because a properly future-proof desktop setup was beyond what I was comfortable spending. (And this iPad will be an absolute beast for a good five years at least, it's so overpowered.) If I had unlimited money, I'd just spring for a pro workspace and commit to spending a week re-making my custom brushes for Clip Studio.