Frame rate dropping when posted

Hello. I've been struggling with trying to get my project to keep its frame rate (60) when i try to post it. I render using Handbrake, and ive tried Media encoder. when i play it on my computer, it's fine. When i play it on my phone, it's fine. but when i try posting it (ive tried Youtube and ig) the frame rate drops to like 30. It's super choppy and none of the changes i made to my render settings worked. My 30 fps projects are Totally Fine though. i genuinley don't know at this point

Also, i render using the frame rate from the project, so that's not part of the problem