Most likely neither - whatever the TV currently has is all we get. An AVSForum user tested it can support 4K 120 HDR @ 4:2:0. We have no confirmation of 4:4:4 as no sources are yet available. If they ever deliver on the promised eARC update then you will have most (if not all) of the 2.1 specs.
When you say most if not all, assuming we get eArc support, what else would there be that we might not get? Reason I ask is I just bought the Q90r but it won't get to me for a few weeks and I have a window to change my mind. Def want to be future proof ish and trying to understand what I won't have down the road and if it matters (to me). Thanks!