Appimage IS an attempt to bring windows style software (mis)management to windows. Flatpak is more like bringing android style app management along with limited permission sets, permission portals, and some sandboxing. It also leverages the server spaces container principals more and more to do!

Guix is also super cool! In fact using guix to build OCI containers and flatpaks to me is natural evolution of the declarative/reproduce able image concepts introduced by both.