Video quality dropping only on phone

Hey everyone, I’m new to posting on TikTok and a social media in general. One thing I found really inconsistent and doesn’t really make sense to me. Is why do everyone else’s videos on my for you page look like they’re such high-quality but my videos when they pop up on other peoples for you pages and including mine, the quality is shit but then for example, if I go on my PC the qualities perfectly fine then my phone it’s not and everyone else that I’m watching has crisp quality showing up for their videos so what do yall recommend me check