I got my first HDR monitor, an Alienware AW2725DF QD-OLED, earlier this year and my experience is that it is extremely clunky to use on PC compared with my PS5 and Xbox Series X. This is because on consoles HDR works automatically for games, movies and even YouTube where it will enable automatically when you watch an HDR video but use SDR otherwise.
On PC, you have to manually enable / disable HDR as there really isn't a reliable auto HDR solution in my experience. All the Windows Auto HDR does is apply HDR to SDR games that don't support HDR rather than being a toggle that turns HDR on for games with HDR. And, yes, you can toggle on HDR and leave it on all the time if you want but I don't want to be using HDR while browsing or using content that doesn't support HDR as it looks way too bright and becomes uncomfortable to look at.
Windows key + Alt + B is basically workaround, allowing me to quickly toggle HDR on and off prior to loading a game or watching a movie/TV show I know supports HDR.
If I had to rate the HDR experience for comparison then I'd say that PS5 and Xbox Series X are 9/10 whereas the PC is more around 5/10, maybe more 4/10. HDR works fine when it on but it just more clunky to use on PC in my opinion.