+1 for Solaar! Logitech should give them money because I would not buy Logitech without Solaar (I'm on Linux exclusively with an MX Master 3S and an MX Keys Keyboard... Crazily each with their own dongle :facepalm:

(Unifying receiver does not unify unifying and bolt so not so unifying eh! Oh and bolt is newer but not backwards compatible, so annoying!))