That's what I did after I realized how much I'd pay for managed databases and auth.

I now have 3 VPS on Hetzner that run about $14/month in total (the old pricing, thankfully). I mostly got three so I wouldn't worry about wiping one if something terrible happens.

Works like a charm. Even with the new pricing, Hetzner or DO would be cheaper than what OP uses. And the maintenance isn't that hard.

Easier to leave vulnerabilities but you can also do it on Vercel and Neon.