I have trouble with simple data update using forms

Welcome!

Hmm, I don’t see any calls to Ecto.Repo that would actually interact with the database e.g. Repo.update/2 to persist the changeset.

And to clarify, Ecto.Changeset.apply_action(changeset, :update) attempts to add the :update action to the changeset – it does not attempt to update the database itself.