When I try to sync to the server the following error will consistently show and fail the sync operation. The same sync error appears across all devices desktop and mobile. Any advice to fix would be greatly appreciated.
You could try deleting this file (ba0bf132e1a344bcb2c1205ca5383ff4.md), maybe that will help. Looks like it's just a revision so you're unlikely to lose any useful data by doing so. But make a copy just in case.
Note that this can happen when you open one of these files in Nextcloud (even if you don't make any change, Nextcloud modifies it), so make sure you never open any .md file
Yes, the next cloud software prefers very strongly that you only use its client sync program on your computer to move data back and forth and make changes to data stored in next cloud. You need to pretend that the directory that you're syncting your files to is invisible inside next cloud. Always leave it alone. See if that helps.
When you choose next Cloud as your synchronization choice in Joplin in actuality it is using webdav and the presumption is that you will not be directly editing the data stored on the webdav next Cloud Server.