If you read the Support and Help Start Here page you’ll see rather clearly that Ubuntu 20.04 LTS isn’t on-topic here.
Ubuntu 20.04 LTS is in extended support which is provided by Canonical, not Ubuntu.
Recovering data from a 20.04 system I would see on-topic, but your desire seems to be booting it so it can be operational; and we can’t help with that as its not a release in standard support