Found a possible solution:

Pros: Flow is fixed
Cons: all my stuff is gone (though this may have to do more with the emergency reset I did? I'm not sure whether that would have impacted my stuff since I couldn't access Flow with my phone either until I connected to my laptop browser)

1. right click on a link/image/anything
2. click 'send to my flow'
3. Flow started up instead of giving me the issues tab; I manually typed in the connection code (scanning QR code gave me an error message and couldn't connect)

Flow is now working, but starting from a blank slate.

Opera GX user here. This has been my problem too! It's been a few days now and nothing has worked. I've made sure that I'm also up-to-date on the latest version of of the browser, but this seems to be a problem happening across the board. Supremely annoying and upsetting as I rely on My Flow for a ton of things and I love GX, but this is going to be a problem.