No, all sound effects are copyrighted. As a result, it is not “copyright-free” (since there are literally zero sound effects that are copyright-free).
CapCut content is already licensed for usage in your projects. Although it is “free,” there is still a copyright issue. Hopefully, you understand that the only way to comply with copyright while still being able to utilize something is to obtain permission. That’s exactly what Capcut has to offer.
However, Capcut also allows you to extract audio from other types of media. Because the copyrights on the original source need you to obtain permission from the original owner, you can’t utilize that in your YouTube video. Capcut does not remove a user’s copyright protections.