By skyforbes I installed Firefox just to try out some stuff and I enabled the "gfx.wayland.hdr" flag in about:config just to see if it works (I'm using CachyOS/Gnome with HDR enabled)..
..and holy cow I was so stunned to find out that it actually works. I've been using Vivaldi and Brave previously and I had zero luck in enabling HDR but on firefox it just works. Now this is definitely my daily browser with HDR and the great extension support that it has.
Thank you Firefox! Keep on rocking!