Gnome is getting accent color support in Gnome 47. I hope Gnome and KDE have the accent color portal configured correctly so eachother’s apps look right.
Though Gnome’s side comes with two limitations. Accent colors will only be used in Libadwaita apps and those apps need to be updated to follow the standard (though I have noticed in Fedora 41 development version that many Gnome apps are still version 46 but still use the new accents). Second, Gnome only supports a handful of named colors while most other desktops allow any hex value. So other desktops will need to pick the closest color.