That server is region locked to japan. You can try kenzato's booru or illusion game cards booru for cards instead.
Edit to add: I just read that in BetterRepack RX5 it connects to the steam server but take it with a grain of salt. It doesn't allow mods, anyway.
F1, find MobAdder, see if there's a way to turn it off in the plugin menu.
Else, just remove it from the bepinex folder, it goes by the same name.
I guess kind of. BetterRepack is portable and has everything in place so that (in paper) you simply extract, open then unzip.
It does come with an optional folder and extras, can't remember if it had instructions, probably has them but it does tell you what some mods do, others link to the respective github page. The extras, iirc, are all for the UserData folder.
Seems it's not installed. Just in case,
You must be registered to see the links
goes to the BepInEx folder.