I think that this reflects your experience. So yeah, there are some issues that you and a few others experience that have not been addressed. I also agree that the iOS application is not great and requires workarounds (those are heavily documented) because iOS is buggy and limited. It’s not unreasonable to expect support, I personally provide support to 5-10 people a week. It is, however, unreasonable to expect everyone to get personal support. You can also contact the EteSync community and get help there (Matrix chan has ~160 ppl and daily activity).
Docker’s whole thing is that it’s an identical environment that you can deploy anywhere, and since it definitely works for at least one person (the Docker image has over 500,000 downloads), it’s most likely something you did wrong. I understand the guides may be a bit rough around the edges, but given the above it’s extremely unlikely that the problem is with the image (which btw, is maintained by the community).