Now you can use transfer packets instead of proxying connections

[BigPebble123]

In the latest Minecraft 1.20.5 update, Microsoft has added transfer packets. The server can tell the player which server to switch to.

Quote from minecraft.net

Transfer Packets

• Custom servers can now request that clients connect to another server with a new packet
• When a client is transferred, it will connect to the target server with a new transfer intent (id 3)
• By default, servers will not accept incoming transfers and will disconnect the client
• This can be changed by setting the accepts-transfers property to true in the server.properties file
• Resource packs are maintained across transfers
• In the case of a transfer, custom servers can skip authenticating again with a new flag in the clientbound hello packet