Your iPhone turns off at 0%.I think you misunderstood me. I said that my iPhone SE 3 shutted down after 5h, meaning that it reached 0% after 5h. It wasn’t an unexpected shut down at all.
However, after other runs, it holds the battery between 7 and 8h which, for an SE 3 with battery health at 85%, is quite good! So I’m actually quite happy with iOS 26.2 (non-beta, I never install betas, only really stable versions using the IPSW file, a clean install).
And that looks like way too short for a run.
I’m glad you did the IPSW restore to see something evens out.