So is the Nintendo switch, Epic released fortnite on every imaginable platform, including my samsung smartfridge, so let’s be honest, the only real reason is that supporting the steam deck is directly supporting the store front they’re trying to go against, otherwise the dozen or so million desktop Linux+Deck gamers would have been acknowledged by Epic long ago.
It’s simple. Go to Tachiyomi and create a backup. Then, in Mihon, during the first setup, it should give an option to restore backup. You can also resotre backup in Mihon settings, then go to extensions and (trust) the restored extensions.
It’s pretty much the same app at its core. So no need to change file names or formats. Everything should transfer.