I've spent some time to deploy shared ccache for our Azure Devops PR builds as well as locally. The 1 hour build time went down to 5 minutes for release, about 9 for debug. It took another 2-3 minutes to download/upload the shared ccache, so it's still a good 6 time speedup, not to mention that it takes much less CPU.

The trick is to set --fdebug-prefix-map and -fprofile-dir to proper relative paths and then with some extra scripting caches will be reusable across build nodes even if the workspace directory is different for each build.

This and distcc (or IncrediBuild) are a game changer for every serious C++ workshop.

https://github.com/icecc/icecream

I never had the time to set it up properly, but by the looks of it, it should be even better.