Sites like catbox[.]moe are popular and most months seem to fail to cover all their expenses with donations. And that's using cheap hosting (ovh, hetzner, etc, and no CDN), I imagine that your Fastly bill will be higher than theirs.

For this to work, I think you need to find revenue sources right away and run it as cheaply as possible, otherwise you'll run into problems, creating more link rot in the process.

Anyway, I hope you manage to make it work.