I'm not sure if their hosting works for you because you might be serving byte ranges. I think we're paying 2k/month usd for like 300TB/month. Backblaze-to-fastly is free, so no egress.
Love your project, more power to you. I'll be using this for a few side projects for sure.
I don't think this project will ever make $2k per month. TBH, I'd be happy it it ever reaches $200 per month. I have to be very careful about what hosting providers to use and CDNs are out of the question.
https://docs.hetzner.com/robot/dedicated-server/network/10g-...
As for other cdns - I remember https://neocities.org/ built their own cdn - but I couldn't immediately find a blog post about the cdn, or something related in their GitHub (unless every node runs part of it, which would make sense, I guess).
They could use you as a PoC/demo for their serverless stuff. Same with cloudflare.
It's worth it to ask. I can send you the contact for our fastly rep if you'd like.
Maybe it's worth front-ending it with cloudflare free, just to see/measure cache hits/requests/bandwidth?
In addition to Cloudflare, bunny was on the radar too.
I believe Hetzner should not have any problem with using 100 mbps out of the 1 Gbps on their servers. That's 30 TB/month for free, per server. It'd be $300-$1800 per month on Bunny.
Just like the cloud becoming easier to run on your own environments, tons of bandwidth is accessible too.