I host synapse as docker container behind traefik and it works pretty well. I have two users on my instance, have setup the mautrix-whatsapp bridge and federate with the instance of a friend.

The setup was straight forward: Pointing the sub-domain via traefik to the service and in the homeserver.yml enable well-known which announce port https with port 443 instead of 8448.

Does the local transportation company provide an app for iOS itself? Maybe that could be an option for you to not use google wallet.

I have chosen a local transportation company to not use the DB navigator app which is a privacy nightmare and support my local transportation company financial.