[noggin]

Connected one of these to my 7 series LG oled, and I can't get smooth 23.97 playback, it is 10x more glitchy than my ZidooX9S,
Running RC2, selected the resolutions in whitelist, stick set to auto.
Oh audio is out if synch and everything plays back in Dolby Vision, even 1080p 8bit stuff, does any one have a definitive bunch of settings?
Cheers.

Kodi (v18b5)Player/Video -
Adjust display refresh rate: On start/stop
Sync playback to display: Off

System/Display -
Whitelist: All 3840x2160 options enabled (see note below)

System/Audio -
Number of channels: 7.1
Output configuration: Best match
Allow passthrough: On
Dolby Digital (AC3) capable receiver: On
Dolby Digital Plus (E-AC3) capable receiver: On
DTS capable receiver: On

Fire TVDisplay -
Video resolution: Auto (up to 4K Ultra HD)
Match original frame rate: On
Colour depth: Up to 12 bits
Colour format: RGB
Calibrate display: No scale
Dynamic range settings: Adaptive

Sounds -
Surround sound: Best available

System

LG OLED B7
Onkyo HT-S3800
Local NAS but using 5Gz Wi-Fi for the Fire TV

The Fire TV 4K can play the 140 Mbps Jellyfish File without any problems and only starts to struggle with the 200Mbps file.

Kodi has a problem right now causing it to switch to 1920x1080 for 4K HDR videos which is why I disabled all 1920x1080 resolutions in the whitelist.

So these settings (whitelisting only 2160 settings) seem to stop the sticky playback, although I did keep yuv instead of rgb, but a) we don't get resolution switching. b) the audio is still out of synch. c) Dolby Vision files only play back in HDR10, does Kodi leia RC2 not support DV from MKV?  

Dual-stream DolbyVision from UHD Blu-ray rips which use HDR10+DV Helper isn't supported on any Kodi platform currently.

Netflix, Amazon etc. are using single-stream DolbyVision (as they know your display capabilities when you request the stream, rather than needing to stream a backwards compatible version) - and this MAY be supported by MrMC (a fork of Kodi) on Apple TV 4K (not sure about other platforms)

Are your MKVs single or dual-stream?