Hi @dachary, this sounds like a neat project. Thanks for sharing.
This is a detailed thread, and it is clear you put effort into it. Have you considered writing a blog post (or something similar) to describe your fedeproxy journey so far? I think this will be easier for you to receive feedback and comments on a narrative instead of detailed policy and project reflections. Generally, I find it hard to comment on other communities because every community has its own context.
You may be interested in opening this as a discussion in the Sustain OSS community too.