A true HDR monitor must employ a special display panel with high dynamic range and a wide color gamut, along with being calibrated for PQ and HLG. For example, the LUM-310X (dual layer LCD system) and LUM-310R (LCD with local dimming backlight system) are capable of reproducing a peak luminance of 1,000 nit and 2,000 nit respectively, and a contrast ratio of 1,000,000 : 1; in addition, they cover 99% of the DCI color gamut.
Other monitor utilizing displays with normal luminace range from 0.1nit up to 400nit or high luminance monitor with up to 2000nit with variable black level (0.1 ~ 1.5nit) is defined as 'HDR Emulation monitor' in TVLogic although they have HDR EOTF and related functions. Below is a simple example for your reference.