OK I'm sorry, it works now! I guess was so tired I thought I had rebooted the Rpi when I did not. After a reboot, it works :)
Sorry! And I hope this helps the next person who purchased this cheap Chinese knockoff to get it working on their Rpi!
The same issue happened to me today, so I started finding a solution and found your question.
This post helped me https://www.raspberrypi.org/forums/viewtopic.php?t=34061.
Open your config.txt file from the boot and the below lines.
Try the alternate HDMI port. It worked for me.
Please download the latest version of the driver, I tried different versions, and finally only the latest official driver version works (http://kedei.net/raspberry/raspberry.html). I uploaded it to Droplr, you can download it from here: https://d.pr/f/kh5JbR
but here i am with a strange strip.
You are supposed to plug that strip into the display port on your Pi. Not the HDMI, but a little plug on the Pi itself.
Also it looks like you should plug some wires into the GPIO to power the screen.
The official instruction video is here.