Hey @Antonio37 ,
I came across your question the other day and spent the past few days investigating this. Unfortunately, I haven't been able to find a solution that works for me, however I have a couple suggestions for you to see if it would work for you.
First off, maybe check your Canvas account settings, and see if there are any access tokens with teams. If there are, delete them, as this will allow you to logout of the wrong account. However, if this doesn't work, the only other solution that I personally have would be to reach out to their support team and see if there's anything you can do. Because you're right, it's almost as if you are 'locked in' and can't get out.
Hope this helps point you in the right direction, best of luck!
- Noah