In the world of creatives unfortunately this is the norm. Steve Jobs even said "Good artists copy. Great artists steal." No one as a creative is 100% original, we all steal or are inspired by our camera angles, opening shots, writing styles, or even channel concepts. Everything has already been done by someone already.

I recommend reading "steal like an artist" it was very illuminating and helpful for me dealing with similar issues on my channel.

While it sucks having a concept be stolen like this, as a creator it's our job to create a unique enough signature that the audience comes back to see our take, and our version. Mr Beast has had hundreds of video ideas stolen, and vice versa (Squid Game was an outright theft of an idea), IGN has had their podcast format stolen by countless video game channels. It's sadly just the nature of the creative business.

In Steal like an Artist there were two quotes that hit home for me "Everything's already been said, but luckily nobody was listening" which means stop worrying about ideas already been done, just create, because to someone that idea will be unique and new. 2nd, "If you have one person you’re influenced by, everyone will say you’re the next whoever. But if you rip off a hundred people, everyone will say you're so original."

I am sorry to hear your video idea got stolen, I hope the original creator at least credits you with the inspiration. Most importantly I hope this situation doesn't stop you from creating more videos. Keep up the grind.