Check out Samsung C27HG70. It has 1440p, HDR, 144Hz and Freesync.
Incase you didn't know, you need an AMD GPU for Freesync to work. (Since you asked if HDR was brand exclusive, which it is not.)
HDR in Windows 10 will probably be improved in the new upcoming "Fall Creators Update" which arrives in 2-3 weeks.
But, please remember HDR won't be very good unless you use an OLED TV or a proper HDR TV with 300+ FALD zones, since there aren't any monitors which does it properly yet. (and probably won't until OLED monitors arrive.)
HDR will help image quality, but not as much as on a 1400$ 4K HDR TV.