HDR is overrated IMO. I even turned HDR400 off again because it's too bright for me. I like my monitors to look like a picture on the wall, not like a torch shining in my face. HDR may be good for pure entertainment on TVs, but if you're also doing some work or even just surfing and reading text, it hurts my eyes. And I'm too lazy to switch it on and off all the time.

The successor to this monitor is coming soon. It will have HDR 600. I would wait.

I have an LG 27UK850-W with HDR and "Fake" HDR. With games like Horizon Zero Dawn, RDR2, God of War (all PS4 games) I have noticed that they all look a lot better with the fake HDR. What I haven't tried yet is playing RDR2 in the PC version on this LG 27 monitor and comparing HDR vs Fake HDR. However, I think these will also be much better with the Fake HDR.

No, just a "fake HDR", if you want to put it that way.