Generally, any flat IPS 27 inch 1440p 144+ hz are as good as the one next to it. If you want to be sure just pick something LG, MSI, Gigabyte or Asus, most of the time they will perform more or less the same, just pick the cheapest or one that fit your asthetic preference.
Just make sure that they are IPS - not TN, not VA (well not the cheapest one anyway.) Not that they were bad but you'll probably do a bit more research on those two to find a good option. But 27 inches 1440p with 144+ hz will perform great as a rule (and not too cheap, not that I know of anyway)
HDR is well beyond you at this price range, it's not totally useless but you can at most expect a wilder colour gamut and extra brightness at the low to mid price range. Not worth the money but all of them tends to come with one anyway.