Maintenance - diagnose/repair functions - suggestion

Some days ago I have had a first freezing of CL. Only a hard power-off with power button for more than 4 seconds was possible. By this file system could be damaged and more.

Now my question is: Which diagnose and repair functions to use after such an issue/event?

What about file system check in CL? How can it be forced?

What about other diagnose and repair functions in CL?

I had to use: “flatpak repair --user” and “sudo flatpak repair --system” which did some repairs. Flatpak isn’t stuck on always wanting to update to Gnome 3.34 anymore now.

I used also: “swupd diagnose” and “swupd repair”. After that keepassxc changed its appearance.

What else to use/do to diagnose system health systemwide in CL? What else to repair parts/functions/databases etc. in CL?

And when to do this? a) After a freezing and power-off? b) on a regularly basis?

What can be done to have a healthy system?

Please add instructions/tutorial under maintenance
May be this should go under " Fix a broken installation".

Thank you.