Comment 1 for bug 1996590

We'll need to consider how to move forward with this.
K8s charms *do* have a series, and the current designs do intend to keep that.
Machine charms certainly have a model where 'juju refresh' stays within a series/base boundary.
It would be reasonable to loosen that for K8s charms, though we'll need some discussion in that space around "universal" charms (where you can deploy a charm and not care whether it is going to bare metal, or to a K8s environment).

As for the 'not finding jammy' when specifying "edge" that is a different charmhub bug. Specifically, the default base selection for charmhub only looks at bases that have been released to "stable" even when specifying "edge".
So Juju says "give me something on edge, but I don't know what base", which Charmhub replies with "possible bases are: 20.04", and then juju comes back and says "give me something on edge from base 20.04".

We have a separate bug tracking the ability for charmhub to give a different base selection based on the channel of the charm that we are requesting. (bug #1981579)