Yes, I have used the arm version.

It is like Virtualbox only, but exclusively for apple silicon https://mac.getutm.app/

It is pretty polished to be daily driven. However you might miss some more features in settings and such if you're coming from something like KDE.

And what about the data? What is the best way to manage them?

Ya perfectly, without any issues. Because the distro uses directly MBP's wifi ethernet style.

They have released a newer version with COSMIC as the default DE

Yes, I have an extra copy of the data in an external hard drive.

I used to have issues when I tried to run fedora and ubuntu, hence the title.