A friend of mine bought IEMs with a microphone (Moondrop Chuu) and it would pick up radio frequencies that you could hear through a voice call. These didn't end up fixing it, I suspected it was bad grounding but we never ended up solving what the root cause was.
Using Safari also lets you do background play with iOS's integration by un-pausing the video in the control menu once you exit Safari. Normally it's a premium feature. Fortunately, the quality difference doesn't affect this.