Thanks for your commentI
it was very difficult to assemble this img, because my experience with this type of device equals zero, everything was explained to me by other users, as far as I understood the quality of the video is given by the level of similarity that the Linux (LibreElec) dtb has with that of android, on android the video is very good, on Linux no, because there are differences in the compilation of the dtb, which can be given by the lack of drivers or other reasons I don't know, I don't know if there will be progress regarding the video, I also noticed this problem.
The dtb files: I found them here, check in pages Armbian for TV box rk3328 - Page 20 - TV boxes - Armbian forum,try to ask an update ; the more expert users are balbes150, hexdump, easyb, amirul
[do you know how to select another dtb file? You can test another dtb file if you want to contribute]
also I hope there are improvements. Best regards!