A big thanks to you all !! I was a newbe regarding libreelec and kodi. But the Beelink GT1 Ultimate did not work on android (7.1) with Kodi, audio passtrough did not work (no DTS).
Then I searched for the right device tree, which I thought would be the 3/32G variant. But with that the Beelink did not boot.
The I added the gxm_q200_2g.dtb and renamed it to dtb.img and added it on the micro usb.
And finally tried to boot the Beelink again, with some searching for the reset switch. Which is located at the bottom, and only reachable with a paperclip!
And yes, LE and Kodi where live. on 1080p/60Hz
With audio/DTS passtrough via pcm and full functionality (ethernet interface, remote control, wifi, usb).
For me this is currently fine, and i am not sending the Beelink GT1 Ultimate back to GearBest.
I did not try H265 and higher display resolution yet. Also did not try downscaling from 2/4K to 1080p yet.