Your brain isn't broken, I promise. During sleep, it actually does process the impressions from your day - that's a normal process. Videos from social media get mixed into that stream of information along with everything else you've seen and experienced. So it's no wonder they sometimes show up in your dreams.
But there's a nuance that matters more than just the fact that information gets processed. When you watch videos right before bed, your brain is in an excited state - the screen is bright, content is changing rapidly, emotions are all over the place. This interferes with your normal transition into deep sleep. On top of that, the endless feed keeps your attention wound up, and it's harder for your brain to switch into recovery mode. That's why dreams become more vivid and memorable - they kind of get stuck in active memory.
Try putting your phone away an hour or two before sleep - at least experiment with it for a couple of weeks. You'll notice that your dreams either stop being so "video-oriented" altogether or become less intrusive. This doesn't mean the process of information processing itself is wrong, it just means the conditions for sleep will improve.