Any way to make Iphone record video in MP4? Choosing "most compatible" format in the camera settings does NOT work!

Seems everyone answering this question believes the "most compatible" camera setting will cause videos to record as MP4 instead of MOV, and it simply doesn't work. I have an Iphone-SE running ios 15.6.1 currently, and despite the most compatible setting, and also setting the lowest video setting the phone allows (720p HD at 30 fps), videos are always stored in MOV format. Since others have asked this same question for years, and are given the same advise about the settings, can anyone suggest another way that works, or a way to complain to apple that this feature doesn't work? Or, is there a FREE app that will convert the video?