YouTube shorts and Instagram reels are a rip-off of TikTok.
Live streams. Twitch is built around them, but you can also do them in YouTube and Instagram.
Stories. I don’t even know who did them first, but now they are identical in Facebook, Instagram, and Whatsapp.
As much as they all copy from each other, it’s never a 1:1 copy. The copy is almost always slightly inferior to the original. Even if they all had exactly the same features, they’d look or function slightly differently. I do wish they’d stop copying though. Keep them seperate because they’re all meant for different purposes. At least, they used to be at one point.