I've had audio sync issues on kodi myself-- specifically osmc on Vero V which is optimized for playback. I tried checking my notes, because it was some time ago. Nothing definitive, but it may have been related to a random crashing issue that turned out to be a bad hdmi port-- which was the last thing I considered checking after triple checking everything else. Anyway, good luck with the troubleshooting. Audio sync issues are a pain but I can also attest yt-dlp has been solid.