[boronine]

I went down this rabbit hole before, you have to ignore all the recommended approaches. The real solution is to have a build server with a global Docker install and a script to prune cache when the disk usage goes above a certain percentage. Cache is local and instant. Pushing and pulling cache images is an insane solution.

[oftenwrong]

What you are describing is basically remote buildkitd. That allows all of your docker builds to share a big cache. The cache-to/cache-from approach is of limited usefulness.