It seems the best route... just start over, and it should all work fine.
But don't forget @Lord Boltar's tip... your 21.04 is a short-term version. It will stop getting updates in January. After you get things working, it would be a good idea to start over again, but use the 20.04 LTS version... it will be updated until 2025.
But don't forget @Lord Boltar's tip... your 21.04 is a short-term version. It will stop getting updates in January. After you get things working, it would be a good idea to start over again, but use the 20.04 LTS version... it will be updated until 2025.