I have a work GitHub account and a personal one. First I used the personal one for test projects, then I moved on and did a repository with the other account on the same com
If changing the SSH key associated with the account doesn't work, change the email associated with the account.
Go to Github > Account Settings > Emails and verify the email address you are using to commit matches the email on the account.
To see what email address you're using to commit, run the following command: git config --global user.email. If you need to change the email address that you are using to commit, run git config --global user.email "your_email@youremail.com".