LE 8.1/8.2 and master have a patch to backport the autonegotiation from samba 4.7: samba: backport default to SMB3_11 from Samba 4.7 · LibreELEC/LibreELEC.tv@d48c3d8 · GitHub
So if you have no 'min' or 'max' protocol in your config it will try to negotiate smb3.11 first and work down the list on failure.
That is awesome, thats alot of improvement on smb part then.
I didnt run 8.1/8.2 yet or 9.0 alpha, so didnt know what versions were in those.
I might go install this one today and try it out.
Still doesnt hurt tho to put a min protocol of smb2 in there.
So it will never use the lower less secure ones, cos default is core wich is the absolute minimum.