Do you mean MySQL 8? I don’t think there is a v10!
Also, what is Nextcloud looking at? Are you sharing/syncing a movie directory? A document list? Is there any filename that is using an unsupported character set?
Depending on your set up, you might have added a file using MacOS or Windows that is using a character that isn’t recognised by TrueNAS. I have a similar set up to you (FreeBSD 13, PHP8, MySQL8, Nextcloud23) but haven’t come across this.
Your error specifically states there is an invalid character in the path. Take a look at the paths Nextcloud is looking at. Maybe even copy the path and paste it into Notepad or some other text editor. They’ll often throw an error and tell you what the issue is.
Alternatively, I’m going to guess MS Office has replaced a hyphen (-) with a fancy hyphen (–) or something similar. That will make your path appear normal while using MS-specific characters. You’ve copied and pasted a name/title and you’re path is now using an unrecognised (invalid) character.
Good luck! These things are never easy to resolve. The best thing to do is go back to basics and re-add components until things break. Maybe just go back to only sharing “/usr/home/asbasnowe/files” or something, and then add shares until something breaks?