So it depends on the specific HDR encoding used, Rec2020 is the most common ones you'll see (It's meant for "pure" setups, i.e. where the source and output are tightly linked, e.g. gaming consoles or blu-ray, or so) and the raw data won't look great. While something like HLG (Hybrid-Log Gamma) is designed for better fallback (As it's meant for TV broadcast, where the output device is "whatever TV the user has"), so should just look dimmer.

This is a HDR screenshot I took of Destiny 2, which uses Rec2020, tone mapped to SDR

And here's the raw screenshot data from before tonemapping.

If the second image had all the right HDR metadata, and the viewer supported it properly, then both images would match.