picking up signals that even Protonmail is not as clean as it might be.

Source?

Fedora Silverblue with a blue image https://universal-blue.org/. It comes with codecs and Nvidia drivers pre-installed.

The system is immutable, so you can roll back to the previous version if an update fails. All GUI applications are flatpaks and you install developer tools via toolboxes or distroboxes.

Ublue images are not one-man distros, they are silverblue images with pre-layered stuff for convenience https://rpm-ostree.readthedocs.io/en/stable/. You can also build your own silverblue image.