Videos not playing on iPhone in any app

I recently bought an iPhone, and everything was perfect for the first few days, but after a week, I noticed a strange issue… Videos in the gallery wouldn’t play (even though my Wi-Fi works perfectly), but I thought it wasn’t a big deal. Then, I realized that videos wouldn’t play in any app—whether it was YouTube, TikTok, or Telegram. I’ve tried every single method I found online, but nothing helps. I already regret spending the money (((

[Re-Titled by Moderator]

Original Title: Videos won't play