I consequently avoid non ascii characters - but you may be able to use what @FadeMind commented on the old forum
Avoid non ascii with shares - but that said it could be that systemd-escape is capable of creating the correct naming - you would have to try it though.
$ systemd-escape -p "share name with spaces"
share\x20name\x20with\x20spaces
The user is one part of the credentials to access the share and under Linux permissions are either no access, read or read/write.
When you mount using fstab or systemd the mount is created by root - thus making the content served from the remote share owned by root.
To tell systemd the particular share is writable you use the file_mode and dir_mode options.