Hello anispwyn,
Welcome to the Samsung Developer forum!
Based on the TV model number, you have a 2024 TV and access to developer mode has changed.
On a 2024 Samsung Smart TV,
- Open Smart Hub
- In the top banner, click Apps
- Find and click Settings (probably at or near the bottom of the page)
- Use the remote to enter 12345
- From the pop-up window, you can enable or disable developer mode
For TV models earlier than 2024, see this page, TV Device, for more information.