Similarly it happens to me with development built on iPad since early this year with UE 5.1. Before, it ran smoothly but since then I am seeing a stuttering every 5 seconds. I tried the above mentioned solutions but that did not help. Tested with basic starter content only - still stuttering. I am wondering if UE5.1 is not keeping up with the IOS 16.2 update?
Also, when I set “Metal Shaders Standard To Target” to IOS 16 and “Minimum IOS Version” to 16, deployment on iPad fails.