To enforce the use of Edge, they're using URLs with the "microsoft-edge" scheme. Some time ago Microsoft made it impossible to reassign this scheme to another

To enforce the use of Edge, they're using URLs with the "microsoft-edge" scheme. Some time ago Microsoft made it impossible to reassign this scheme to another app like EdgeDeflector. PS: It was KB5007262 that "addresses an issue that might improperly redirect OS functionality when you invoke microsoft-edge: links."