Unless you’re making Instagram content, very few photographers use HDR. Everything else will look the same on both screens.
I think you may have mixed up mini-LED backlighting with OLED and microLED displays. mini-LED backlights merely allow for better local dimming of the backlight behind an LCD, but the number of independently variable backlight zones is still orders of magnitude smaller than the number of pixels. Over short distances, an LCD with local dimming is still susceptible to all of the contrast-limiting downsides of an LCD with a uniform static backlight (and local dimming brings new challenges of its own).
OLED is the mainstream display technology where individual pixels directly emit their own light, so you can truly have a completely black pixel next to a lit pixel. But there are still layers and coatings between the OLED and the user, so infinite contrast isn't actually achievable.
microLED is an unsuccessful technology to provide the benefits of OLED without as many of the downsides (primarily, the uneven aging). But nobody has managed to make large microLED displays economically yet, and it doesn't look like the tech will be going mainstream anytime soon.
The appearance of a lone mouse cursor on a black screen in the dark is mildly amusing for exactly this reason. You can watch as the ghostly halo of light follows it around the screen as you move the cursor.
I'll upgrade my machine when they put an OLED display in it.