I think you should investigate Windows settings more carefully, rather than the game. My default browser is Firefox, and Canvas always opens in it for me.
I just spent two hours investigating them
Everything is set default to opera, even going to browser settings in opera assures me it is set to default.
Nothing BUT inzoi forces edge
What can you say? It’s Microsoft and their desire to promote their browser by any means possible.
But what happens if you set Chrome or Firefox as the default browser instead of Opera? Will Edge still be used anyway?
Try checking the registry as well. Maybe it will help? Windows 11 continues to default back to Edge. How to I change it permanently to not use edge and only the browser I select. - Microsoft Q&A
Yea microsoft sucks, I will attempt with a different web browser once the game finishes re-installing. Thanks for trying to help me out 
Have you tried editing the registry as suggested in the advice above? Or is everything fine there?
Maybe try checking the system files? Through the console as administrator: sfc /scannow
You might even need to reinstall Windows, it’s hard to say at this point…
I am not sure if I trust myself enough to mess with the registry, don’t want to accidentally mess up anything. I don’t think this is worth re installing windows for either?
I wish they would give us an option to change whether it opens browser or stays in game or at least force it to run on a specific browser instead of ‘system default’ if the systems are this stupid.
How to resolve uploading work E05?
Unable to upload works normally, displaying E05