That's a good long term question, but in the short term I think a lot of late 2020 and early 2021 releases will have One X patches.
Here's the big showdown I'm waiting for. Cyberpunk Xbox One X vs Xbox Series S. Only one man can settle this, John Linneman.
Yes it will be interesting for sure, and even at different resolutions:
What will the S look like final product on a 1080P set?
Will here be a 1440 mode?
Will there be an up-scaled 4K mode, and how good will it look if it's stemming from 1440P?
And maybe not just pixel counting, maybe they should add to the testing, real world test on different displays, one at 1080p and one at 4K, side by side, 55" oleds with the person sitting at 10 feet.
It would be really interesting for them to do some blind tests too with no console visible.