I have bought two Luckfox 7" DSI Touchscreens of Amazon with two Raspberry Pi 5 (and official Power Supply and SD Card).
I wrote and verified Rasberry Pi OS (64-bit) as of 2024-03-15 on the sd card.
I added "dtoverlay=vc4-kms-dsi-7inch" at the end of config.txt.
I supply power to the display (VCC ...