Broken link? This seems to be a more or less up-to-date roadmap for Thunderbird on Android: https://developer.thunderbird.net/planning/android-roadmap

We use renovate mostly for container images and nuget/npm/maven dependencies.

If it’s relevant for your job, go for k8s. The more you tinker with it, the more knowledge you’ll accumulate. Is it the optimal solution for a self hosting setup? Well, it depends but most probably not.