FYI, a similar, though more scoped use case, was presented here: Classic confinement request: communitheme-set-default (communitheme snap). The end result was that classic was not granted and that the proper solution (the design is given here) involves updating snapd to support an ‘alternatives’ interface. While the design is written and it is on the larger roadmap, that work is not prioritized by the snapd team. Of course, anyone willing and able to create a PR against snapd is welcome to do so.