Can you use ethereum for this specific use case? How?

I'm trying to find a way to prove that livestreams aren't prerecorded.

I'm thinking of using blockchain tech to do that. I make a block with a specific hash at a specific time, and I show that specific hash on the livestream, and people will know that I can't have made it ahead of time or predicted it, bc I believe hashes are randomly generated. And if I try to fake the time and date that the block was made in a fabricated prerecording, ppl can look at the block itself and see that I did that.

The thing is I'm really new to ethereum and it doesn't seem to be made for this purpose. Can someone tell me what I'd need to do in order to use it like this if it's possible?