X1 Yoga 4th Gen - 4k vs. WQHD vs. X1 Yoga Gen 7 OLED - thoughts?

[plympton]

I have had a X1 Carbon Gen 6 WQHD Matte. I use this mostly for surfing and YouTube, reading news, etc. Nothing major. I usually have a cord handy or near. Screen quality is super important. That said...

The Yoga Titanium I had for a few days was pretty... terrible. The screen was especially ghosty, and the keyboard was pretty Meh. The screen mostly. The reflectivity was actually pretty good, which surprised me.

I have a gen 7 OLED on order. It's a 30-day return if I don't like it, but I'm not committed to it - I'm concerned about the keyboard (Gen 6 was awesome!). I'm expecting the screen to blow me away.

Gen 4's are cheap. Is the reading experience on either WQHD or 4k bad? Are the screens laggy/ghosty? How's the reflectivity (say, compared to the Carbon Gen 6 HDR display which is like a mirror!)

Is the Gen 6 4k+ any better or worse than the Gen 4/5 screens?