Development builds of Ubuntu 22.10 just received an updated version of the GNOME Control Center (aka settings) app, which includes Ubuntu-specific options.
KDE Plasma 5.25 offers a dynamic new customisation feature that sets the system accent colour based on the colour of a user's desktop wallpaper.
Ubuntu 22.04 LTS includes a much-requested new feature: accent colours. Users can pick from 10 different colours to use in the GTK, Shell, and icon themes.
A choice of system accent colour could be on offer in Ubuntu 22.04 LTS. Devs have already created a working demo to pick an accent colour for Yaru.