The poster is not a format certificate
Movie artwork identifies a production. It does not prove an available stream is HD, 1080p or 4K. Inspect the actual edition offered by the viewing service.
1080p and everyday viewing
Where available, 1080p can be one of several choices. Compare motion and subtitle clarity on your screen. Select a setting that plays consistently rather than one that repeatedly interrupts the film.
4K editions
A supported film edition, application, display and any relevant plan conditions all contribute to 4K viewing. A high-resolution display does not turn an ordinary source into a different edition.
HDR and audio are separate questions
Resolution, brightness range and sound format describe different parts of presentation. Look for the exact options of the selected film. Do not assume that one badge implies every other format.
Automatic quality changes
Some applications adjust video quality as conditions change. Use the application’s supported controls when you want a different balance. Movie4U does not run a second quality selector behind its poster cards.