New Macbook Pro M1...Migration Issue

Reply tabs to reply to a thread discussing this problem are greyed out...says to start a new thread so I thought it may be helpful to some how Apple Support sorted the problem I was having.

Trying to migrate from Macbook Pro late 2015 running Catalina has been impossible...searched here for message I was getting...'migration assistant macbook pro m1 this mac cannot be used to migrate data due to an issue with unlocking this system you cant migrate'

After numerous tries using possible solutions offered here that worked for some but not me I rang Apple support...was told to update Big Sur even though was already up to date.

Update solution didn't work so I rang again.

Support chap took me through solutions that should work but didn't.

He then connected remotely to my machine to walk me through solutions...over an hour later the conclusion he came to was a faulty machine...not a minor problem he said but a major one so the machine to be returned not for repair as I've only had it three days but for a new machine.

When new machine arrives I'll certainly make sure to use set up assistant for Time Machine option that's suggested here to migrate and not the Migration Assistant.