Everything #OpenStreetMap related is welcome: software releases, showing of your work, questions about how to tag something, as long as it has to do with OpenStreetMap or OpenStreetMap-related software.
OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
Join OpenStreetMap and start mapping: https://www.openstreetmap.org/.
There are many communication channels about OSM, many organized around a certain country or region. Discover them on https://openstreetmap.community/
https://mapcomplete.org/ is an easy-to-use website to view, edit and add points (such as shops, restaurants and others)
https://learnosm.org/en/ has a lot of information for beginners too.
I am aware of the guide on their github
https://github.com/organicmaps/organicmaps/blob/master/docs/EXPERIMENTAL_PUBLIC_TRANSPORT_SUPPORT.md
But that is not something I would want to do for myself, much less so the people I usually recommend OM to :/
Is it just the lack of UI/UX or is there actually a quality issue regarding the GTFS/OSM source data?
I would assume that it's neither a UI issue nor a problem with the source data, but rather a limitation of the routing engine.
Looking at your link, it does seem to say that support is experimental.
yeah here is hoping that it comes along and becomes the default