Most of the apps rely on contributors to provide supported locations. I was wondering if a dumb app where you provide the GTFS zip url of your city would be useful. Could work if you stay in your city a lot

e.g. most of what you see on https://www.transit.land/map#3.46/47.78/12.46 is GTFS (hopefully public urls)

Did you try the new 2FA experience they have in beta? https://mailbox.org/en/post/beta-program-starts

Just turn on the mailbox beta in the account settings and you can get regular TOTP when logging into the webui