The only multiplayer I've played so far is Pavlov (Call of Duty type thing). Found myself on a bridge with three other soldiers as part of a team, then they all started talking to each other with children's voices. Closed out instantly.
I might consider trying my ATH headphones, at least for sitting down, although the built-in speakers are very good.
I've noticed most of the 8k videos don't play higher than 4k via the Oculus browser>Youtube, no idea why, and none of them go past 4k on the Oculus YouTube app. Workaround is to download the 8k videos (using Videoproc or similar), sideload them onto the headset and play them through the free video player. About 1GB per 5 mins though.