This Minecraft Velocity plugin (from 200Tigersbloxed) works perfectly. I just modified it and fixed a bug:

• The bug occurred when restarting the proxy—the plugin would try to save the ID again, causing issues.
  
  
• I fixed this, so now it works correctly even after a restart.
  
  
  
  A playit.gg plugin for Velocity servers
  
  Getting Started
  1. Setup a Velocity Server
  2. Install the plugin's latest release
  3. Click the link in the console window to link your playit account to the server
  4. Done!
  What's supported?
  Pretty much anything that's TCP will work right now.
  
  Feature Description Supported
  Minecraft TCP The TCP port for Velocity ✔️
  UDP Ports UDP Ports (for things like Geyser) ❌
  Extra TCP Ports Any extra TCP ports to expose ✔️
  IP Forwarding The actual IP address of the client ❌
  
  IM NOT WHO MADE THAT PLUGIN I JUST FIXED FORKED I HOPE ITS WILL WORK FINE,GUYS