Well I haven’t delved into it too far since our server is still in the beta stages, so I can’t answer all the qualifications. However, I would check out LuckPerms . This is the plugin my server group is delving into and it is user friendly with a well documented wiki. If you cannot find something on the wiki, from my experience the Author will kindly answer your queries if you cannot find a certain feature. It is very similar to Pex and from my experience, however easier to navigate.
I know this doesn’t supply much info, but nevertheless, hope this helps!