Man, I didn't even realize there was a way to run it on Linux. I saw some project (in process) for it on Github and was like "whelp I guess it's not possible" lol.

...I miss Pokemon TCG Online. It worked so well.

Sorry for not actually answering your question lol.

I managed to get it working by setting the .desktop file that wine created for it to be able to accept the tpcitcgapp protocol that the browser opens after you login. Add this to the bottom of the .desktop file: MimeType=x-scheme-handler/tpcitcgapp; I think you have to run some command to update the file type associations, but I didn't remember what it is.

Don't have an answer unfortunately, but i do wonder now if i could get my game running in a similar way with a browser token. I don't play pokemon TCG, but i did like playing this old crusty mmo called Darkorbit, which finally switched from flash to unity like 1 or 2 years ago, but it has the same issue on linux where it can launch just fine and it doesn't use anti-cheat, but it can't load the login page. Last time i looked into it i ended up finding the pokemon TCG issue and it seems to be the same problem, where it's relying on Edge for the login.

Well i'll be damned, just decided to try getting the game to work again, cause after this post i decided to do some searching once more and it seemed someone found a workaround, but it turns out the workaround isn't even needed anymore. I wrote a reply in the github gist here explaining the steps i took. I guess i can now play my mmo slop again if i get the itch lol