Are you perhaps asking from a US perspective? Or maybe Indian too. I don’t know of any other countries where marriage is expensive really.
We got married in Vegas as a fun thing to do, since we’re Swedish. Legally the difference is extremely small between being “sambo” (co-living) and being married, and we could just as well kept going without getting married.
I went from Seafile to Nextcloud with family file sharing as the primary usage. I’m using the AIO docker installation without issues.
This might not help, but I never experienced the issues you had.
(I moved away from Seafile due to - in my opinion - it dying a slow death with less and less support)