thnx but that means all the 4k content on kodi will be 1080?
And hyperion works with this method?
If we cannot watch 4k then why we should upgrade?
A quick test showed that 4kp24 content (tested with Interstellar-divx-hevc-uhd-51ch-4K.mkv) played fine with hyperion active (both at 4k and HD output at 24Hz), but 4kp60 seems to be too much (both at HD and 4k output). So, sorry, reducing the output resolution doesn't seem to help.
If you want something that plays all 4k content with hyperion active then ATM the RPi4 is not the right choice for you. It probably will get fixed at some point but as posted numerous times there's no ETA for the fix.