Attempted to fix macOS startup volume after failed dual-boot Linux install, but failed and now original partition unknown
I am sorry to hear that you are having this issue. Can you access macOS Recovery? If you can, that's great news!

If you can access macOS Recovery, then the first step would be to run First Aid on APPLE SSD/HDD, the Container Disk, and Macintosh HD. If the process fails, then that means that the data might not be recoverable. If you do manage to mount the disk, then that's good news!

If the OS drive mounts, then go to Disk Utility and type cd /Volumes/Macintosh\ HD then type ls. This will allow you to see if your data is still there.

If you can boot up on the macOS Drive again, then that's good and your repair process is complete! If not, then try reinstalling macOS from macOS Recovery. This will not delete your data. Then try booting up on it.

If none of these work, then the last thing that you can do is erase the APFS container, and reinstall macOS on Macintosh HD.

Good luck!