Lost config/state access after chromium snap is refreshed

This is unfortunate indeed. It doesn’t affect only chromium but potentially all snaps, although it’s probably more visible and annoying on chromium.
This is being addressed in snapd with [WIP] Refresh App Awareness. Until this is on by default, I suggest enabling the experimental feature. I’ve had this on for a few months and it works well:

snap set core experimental.refresh-app-awareness=true