Authentication plugin that allows you to set a login username and ignores the player’s IGN and IP?

I’ve looked at many authentication/security/verification plugins, and they all seem to allow users to join the real server before getting them to create their own login password, which they’ll use to login next time and reclaim their inventory. If I understand correctly, this means anyone on the internet can effectively join the server?

The server will have both Java and Bedrock players over Geyser. It’ll be the latest version of Minecraft and it has to be set to offline mode, so I believe whitelisting isn’t an option.

What I think I’m looking for:
- Admins create unique usernames and passwords for each user before they connect to the server.
- Admins give the user their credentials and they login.
- The user’s IGN and IP address are totally ignored, as these can change frequently and be used for impersonation.
- Admin or users can connect (preferably) multiple premium accounts to a single login identity.
- Having your premium account linked to a login identity would allow you to bypass the manual login process.
- The login identity being decoupled from IGN and IP address means you can access your inventory on any device. This isn’t critical, but it would be great.
- Compatible with Geyser and Bedrock players.


Is there anything like this?