OK but we still need the same information even if you are using 20.04 now. Please run:
journalctl -b-1 > prevboot1.txt journalctl -b-2 > prevboot2.txt journalctl -b-3 > prevboot3.txt journalctl -b-4 > prevboot4.txt journalctl -b-5 > prevboot5.txt
and attach the resulting text files.
OK but we still need the same information even if you are using 20.04 now. Please run:
journalctl -b-1 > prevboot1.txt
journalctl -b-2 > prevboot2.txt
journalctl -b-3 > prevboot3.txt
journalctl -b-4 > prevboot4.txt
journalctl -b-5 > prevboot5.txt
and attach the resulting text files.