For no js solution, I think some sort of using optical illusion as captcha could works, especially https://en.wikipedia.org/wiki/Magic_Eye https://en.wikipedia.

For no js solution, I think some sort of using optical illusion as captcha could works, especially https://en.wikipedia.org/wiki/Magic_Eye https://en.wikipedia.org/wiki/Magic_Eye or something like https://www.youtube.com/watch?v=Bg3RAI8uyVw https://www.youtube.com/watch?v=Bg3RAI8uyVw which could cleverly hide captcha answer within animated noise mess. However these methods are not really accessibility-friendly tho.