The premium system also needs reworking.
Now there are several premium groups, such as donators, subscribers, old premium groups..
It is necessary to make a clear separation of permissions and features for each group.
Most likely, the main group of premium with full access to the private section with files will be a Subscription system.
And a user who makes at least a donation without subscribe will receive a permanent stay in the Donor group with extended rights to use the site, but without access to the private section with files.