>>718264334
Yes and no
Oleds will have perfect contrast/perfect blacks even in SDR due to their nature sure, but they're still limited by the SDR luminance and color range until you actually activate HDR and you get proper HDR tonemapping out of whatever media you're watching or playing.
SDR on an oled will still only get you about 100 nits of luminance details and the regular rec709 colors.
Only with actual HDR tonemapping in rec2020 will you get higher frequency details from higher nits over 100 nit. You can blast a display to 1000 nits in SDR and that will be ofc brighter but it won't show you any additional details but in HDR it will, that's why HDR performance is measured in tiny 1% windows, people dismiss it because that sounds tiny, but that's actually what matters the most, those HDR highlight is the most obvious difference, IRL the stuff that actually blinds you for the sun is usually this tiny after all, like sun reflections on car, or the actual leds producing the lights on cars at night. Those are the things where just depicting an SDR image on an OLED won't change anything, you need the HDR signal to tell the TV to use much higher nits on those specific spots.

What I like the most about HDR is how much less "bloomy" everything looks, bloom is a dirty hack for SDR to depict high brightness in a format that cannot depict that level of light, in HDR it can be actually displayed leading to a less bloomy image overall, and the colors are just way nicer, some primary colors look ferocious with higher range of colors + higher nit brightness.