I messed up

You must have done more than rename a partition... it is looking for the partition UID and not finding it. Since the UID is never supposed to change until the partition gets wiped, this is very odd indeed.

Also, putting external volumes (usb stick?) into fstab is not a good idea... let the automount find it when you put it in and want to access it.

I would create a live media if you don't already have one. Boot into that, try to mount your partition and chroot into it. Run

 undefined

    
lsblk -f


  

Look for the UUID of the partition and copy it. Edit /etc/fstab and swap the UUID of the partition with the one you just copied.

Try that. Not a definite fix, but that would be the first thing I try, from memory.

EDIT: this assumes it is your main partition that is not being found, otherwise, you should be able to access /etc/fstab without a live media.

That's funny, I had the same thing happen to me last week -- except I didn't do anything with partitions or disk management. (Ended up installing Silverblue, since it wasn't my primary machine.)

@harrysbalzac Is it complaining that /media/extEXT4drive isn't mounting? If your root drive (/) is mounting and you have access to /etc/fstab, you can just edit that file with the new UUID of the drive.

 bash  

    
ls -lha /dev/disk/by-uuid/  

  

To see what the new UUID is, (assuming you know the device path).