@Harry you don't need to add that line. In the 2026 R1 code, EnablePushNotifications defaults to true when the key isn't in web.config, so a missing line means it's on.
Will's question about the scheduler is the one I'd chase. Processing-screen schedules and Trigger by Schedule business events run on the same automation scheduler, so when both stop at once, start there.
Open Automation Schedule Statuses (SM205030) and look for an Initialize Scheduler button. It only appears when the database was restored from a backup taken on another site, and on that site every schedule stays off until someone clicks it. That fits moving to a new instance. Click it only on the site that should be live. If your old 26R1 site is still running, both sites will run the same schedules.
If there's no button, check two things. In 26R2, both schedule screens show a warning while a maintenance lockout is on, and schedules stay suspended until the lockout is ended on Apply Updates (SM203510). Then check web.config. DisableScheduleProcessor in appSettings should be False. When it's True, the scheduler doesn't start on that site.
I checked this against the 2026 R1 code. The 26R2 release notes don't mention either web.config key.