Is it true that SDR a lot of the time looks better than HDR. Sorry if it's a dumb question but watching videos on the subject on youtube they often show SDR looking better.
Depends entirely on the film/tv show and which region of the film you compare, much like 4k and 1080P too, sometimes 1080P can actually look better than the 4k version.
Also, there is no point watching SDR VS HDR comparison on youtube etc. especially if you are watching it on a SDR display yourself. And lastly, you need to get a good HDR display, not one which is fake HDR i.e. doesn't meet the requirements. An OLED or one of sony's or panasonics high end LCD TVs with full array local dimming is what you need to see HDR really shine.
In my experience, the areas where HDR truly stands out is when there are dark scenes with bright objects i.e. things like the stars in space (passengers), a bright lamp in the back of a dim/dark street (la la land is very nice for stuff like this), neon lighting be that bill boards, shop signs etc. (as in the likes of blade runner, altered carbon).