I have been out of the loop for a while with the development of Linux/GNU based OSes on phones. However, with seeing how companies (like reddit) can change the rules as they wish, I want to see if completely switching to Linux is possible.

Long story short… what are the current phone providers that have Linux as an OS, or what is the best way to run Linux on an off-the-shelf phone?

As a side-question, is Nextcloud still the next best option for a complete service alternative to Google/iCloud?

Thank you!