Documemtation:
https://www.zabbix.com/documentation/6.0/en/manual/config/users_and_usergroups/usergroup#configuration

There are details, yes, but general logic is not obvious at all and not described on documentation.

I.e. it should be stated the Tag settings allow to perform optional and additional limitations to what the user should see.

Also, it should be stated explicitly, that this affects ONLY problems visibility.

Also, a table with example of resulted filters is not clear at all. I feel like it should be split to 2 separate tables.
Also, it makes sense to create an additional table (as 3rd table probably), where will be No visible problems.

Frontend:
Ideally would be good to update strings in Fronted to reflect these details somehow  without forcing zabbix users to read documentation to understand it.

For example, on the tab, "Permissions" could be renamed to "Filters to see problems".
Yes, "Filters", as it's more correct term here. It's not a permission actually.
Using different terms here even will help to separate these 2 different kinds.