This is simply "Disable transfer window" feature that was very ofter requested on steroids. :)

Most important things you need to know:

• Works only in career mode.
• Works only when you are playing with the Live Editor.
• Banned team won't be able to buy/loan-in players, but will be able to sell and do loans out.

How to ban team

• Open Team Editor as mentioned in Editing Team

• From menu bar click on Team -> Transfer Ban.

• Fill the inputs as you wish

• Click "Apply Ban(s)" button

If you want to ban all teams in given league or just simply all teams in the game then tick corresponding checkbox.

How to unban team

If the given team is already banned then the tool should show you different window after you click on the "Transfer Ban" button

So, to unban team/league/everyone click on corresponding button.

LUA Functions

• You can programatically control transfer bans system with following functions:
  • AddTransferBan
  • RemoveTransferBan
  • IsTeamTransferBanned

FAQ

• How can I ban the team forever?

  • Ban the team until year 2100 or something like that.

• Where the info about transfer bans is stored?

  • The file is called transfer_bans.json and it's stored in YOUR_GAME_INSTALATION_DIR -> LiveEditorMods\CareerData\YOUR_SAVE_UID (In Live Editor v23.1.2.4 the transfer_bans.json is stored in C:\FIFA 23 Live Editor\mods\CareerData\YOUR_SAVE_UID)