I'd recommend reaching out to customer support. There's no guarantee they'll be able to fix either, but at least it should help prioritize their engineering team in working on those problems. The second one sounds like maybe a driver isn't configured for video decode acceleration (or maybe some kind of audio configuration issue could be causing sync-related problems?). The keyboard - I have no idea, but maybe they can fix it with a driver or BIOS update.This year I bought the Snapdragon based Lenovo Yoga Slim 7x. The Yoga 14" 4K OLED display is amazing, but it has frustrating stability issues that make using it painful to use at times. The keyboard disappears and is only recoverable by booting into the BIOS. The processor begins to glitch rendering videos in bursts with pauses.
Speaking of driver updates, have you ensured you've got all the latest? I don't know anything about Lenovo, but we use Dell at my job and they have an updater tool you need to use, because a lot of the driver & BIOS updates won't appear through standard Windows Update.
Good luck!