I have a public SMB share mainly as a media dump. Everyone can read and write, without any auth - as intended. However, if I copy files via SSH (as a regular user, not the samba user), these files are of course owned by that user and thus not writable for the samba user - so I can't touch these files via SMB.
My config looks like this
[public]
path = /path/to/samba/public
guest ok = yes
writeable = yes
browseable = yes
create mask = 0664
directory mask = 0775
force user = sambapub
force group = users
I can fix the permissions by simply chown/chmod all files, but that's not really a solution.
My hacky way was to make sure group ID on each computer matches and have the directory writable by the group. I also make sure user ID is different so I can identify who created it. It was easy for me because I only have to worry about 2 computers plus my NAS.