The log and screenshots show that you forced the desktop to 4K@30 and there is a single whitelist entry for 4K@30 .. which means you're attempting to force all media to play at 4K@30 resolution with Kodi upscaling everything itself. It's a recent i7 CPU with 16x cores so it has some grunt, but media apps aren't as multi-threaded as you might assume, so regardless of the specs that might not work, and processing e.g. [email protected] media (most movies) to 4K@30 requires a lot of compute. The log doesn't show any playback, so hard to comment on what goes wrong, but..
I'd recommend setting the desktop to 1080p and then whitelisting 4K@30/29.97/25/24/23.976 and 1080@60/59.94/50/24/23.976 and allowing mode doubling (hence 1080@25/29.97 are not required). That should allow Kodi to switch 1080/4K to native resolutions as needed, and the only stuff that won't be handled is 4K@60/59.94/50 which requires HDMI 2.0a capabilities in the AVR/Projector.
All suggestions long documented in here: https://wiki.libreelec.tv/configuration/4k-hdr