Shell Header update does work outside of a Ticket, as it should, since it has nothing to do with Tickets.
You might need to “refresh” by Navigating somewhere.
For example, I have a button on NAV screen that prompts for new WiFi PW and when it completes the change, the Shell Header is updated to contain the new PW. I have a different DB loaded now, so cannot say for sure, but I might have put a Navigate Module Action set to NAV screen at the end of the flow to “refresh” the UI.
And/Or it might be that I monitor Application Screen Changed Event (no constraints on the screen) and do all Shell Header updates in that Rule.