macOS Big Sur Terminal command 'open' behaviour changed and I don't know how to get back to how it was in Catalina
For now it seems that open -n someapp.app was the solution. I'm not sure if I will run into issues later down the line where I'm not able to use this command but it works at the moment.
Thank you @nohillside for the idea.
UPDATE: What I've done is alias open=&quot;open -n&quot; and it seems so far that this is now working same as it was working pre-Big Sur :)