Saving is real in euros, but count what you take on: OS updates, backups, monitoring, zero-downtime deploys, DDoS/bot handling, and being the one who gets paged. For a vibe coder that's the hidden cost.
At $40-55/month I'd first look at why function duration is high. Common cheap fixes: streaming AI calls holding functions open (enable Fluid compute), slow DB queries from a far-away region (put functions in the same region as Supabase), uncached pages.
If after that it's still $50+, Coolify on a VPS is reasonable. Keep the DB managed (Supabase) so the VPS holds nothing you can't redeploy.