The viewing angles on TN monitors are better than they used to be, and it doesn't matter as much cause you're going to be able to control what angle you're looking at it pretty well. The tradeoffs are worth it for the lower costs and higher frame rates I feel, though you can get a nice 60hz IPS for not too much.

The HDR you're thinking of is a different kind of thing to like, the display technology. That HDR hasn't really come to monitors yet, but I have an HDR TV and it's extremely cool. The difference is in the backlighting, in a conventional LCD screen it's just one uniform lamp, in an HDR screen there's multiple lights that light different parts of the screen differently (or if you're talking about an OLED screen, each individual pixel has its own brightness). Content with HDR data will be able to tell the display how bright each pixel should be, so you can get dark or bright areas with fine detail. Even for content that doesn't have HDR data, a good HDR screen will be able to make it look good basically by guessing how bright or dark part of the screen should be.

It's worth mentioning that a lot of TVs have HDR labels but like don't really do much with the data, you kinda have to read reviews to know if it's any good at it. My TV is a midrange kind of thing, it doesn't have a ton of dimming zones so sometimes there's halos around things (you can notice this with like, white lines on a black background) but wow I still love the effect. The purpose of a display is to throw light around and HDR just does it better.

Sorry to uhh, kinda geek out lol. There really isn't an HDR monitor worth getting at the moment, but it's something to keep an eye out for in the future.