If you aren’t familiar with Immutable operating systems, well here’s the shortest way I can describe it: Immutable Linux refers to a type of Linux operating system where the core system files are set to be unchangeable, or "immutable." This means that these core files cannot be modified during regular use, which helps in preventing accidental or malicious alterations. This approach enhances security and stability, as it reduces the risk of system corruption or attacks. Users can still install and update software, but these actions are typically handled in a way that keeps the core system untouched.

Very well put!

The Firefox install (although lacking any detail) may be

• missing "use portal" setting in about:config
• missing decorations so it saves space but the Gnome style ones suck as the hitbox is not in the corner

Kubuntu really is a mess, dont recommend to anyone. Their installer sucks! And its like, one of the most known Distros...

I recommend the SyncThingy Flatpak, it just works.