Depending how your rights are assigned you could use the Extended tools ctrl. + alt. + x to Reset the ACL's of files and directories or depending if you want full ownership of the files and directories use this option to Set owner. But this should be tested with a new share and set a different owner as not to disturb the existing rights to the directories that users have currently so you understand what is going on in your SAMBA server as this sounds like a preexisting condition. Please read the below statements and read the documentation of you SAMBA server on how this relates so you have a better understanding. We do not handle permissions only your server but this will help.

note:
Resetting ACL's will reset all file permissions. It works like chmod
777 in Linux shell and it is connected with file system.

Set owner of files is also connected with file system and it works
like chown in Linux shell.

Permissions in Web GUI are only connected with Samba, not with file
system.

Also have tried to enabled and set Superuser in the Function „SMB settings“.
This also sounds like there where previous permissions in the past and or the administrator security setting where updated and the SAMBA server is keeping them, the workaround that you are doing is proving this and you may have to continue with this process unless you change the authentication method Internal LDAP (import users and groups) to test UID 0. Also unless your External LDAP has some type of cryptography that has been update recently, which we do not support this could be contributing to issue.