No, posting things (for example on YouTube) counts very well as prior art and helps you invalidate (or limit the scope of) patents that appear later.
For a well-known case, consider Hangprinter, by Torbjorn Ludvigsen: a 3D printer without a frame. He had built it and documented the whole thing in YouTube videos. Then someone heard of the idea and went ahead and got a patent on it.
Torbjorn turned on the Internet for help, started a GoFundMe campaign to collect resources, and with the help of an experienced attorney, managed to have the patent limited so much that does not affect almost any other printer. The "experienced attorney" part was the most crucial, in my opinion, and he could not have chosen anyone better than the one he used.
For a well-known case, consider Hangprinter, by Torbjorn Ludvigsen: a 3D printer without a frame. He had built it and documented the whole thing in YouTube videos. Then someone heard of the idea and went ahead and got a patent on it.
Torbjorn turned on the Internet for help, started a GoFundMe campaign to collect resources, and with the help of an experienced attorney, managed to have the patent limited so much that does not affect almost any other printer. The "experienced attorney" part was the most crucial, in my opinion, and he could not have chosen anyone better than the one he used.
You can read all the details in the entry named "Patent Got Narrowed 5-8-2023" on Torbjorn's blog https://torbjornludvigsen.com/blog/