Thats the official DJI account. Altitude limits can be temporarily removed by DJI for specific locations/dates if you contact them with a legitimate permit to do so. They probably used the same function for themselves to make this video.
I downgraded my firmware to the previous version 01.00.0300 from September, 2025. It still show the 500 m limit. I've tried restarting both drone and controller to no avail. Could the controller firmware also need to be downgraded?
If you're using DJI Assistant 2 then the program downloads them, it should show you a list of the firmware versions available.
If DJI Assistant 2 doesn't show you previous firmware versions available then you could try using the free dronehacks...