On ZeroFS [0] I am doing around 80 000 minutes a month.
A lot of it is wasted in build time though, due to a lack of appropriate caching facilities with GitHub actions.
[0] https://github.com/Barre/ZeroFS/tree/main/.github/workflows
ZeroFS looks really good. I know a bit about this design space but hadn't run across ZeroFS yet. Do you do testing of the error recovery behavior (connectivity etc)?
I found that implementing a local cache on the runners has been helpful. Ingress/egress on local network is hella slow, especially when each build has ~10-20GB of artifacts to manage.