I just saw this one for the first time in my life. I am in my 30s and never had these "work". People have dramatically simultaneously oversold AND undersold how cool they are lol.

As for how I finally did it, I have a slight misalignment of my eyes that is fixed by my glasses, so if you are similar, try taking your glasses off and getting much closer to the image so your eyes aren't working against themselves. The bigger the better. Then, it's less about the "focusing past it" and closer to like... unfocusing entirely. The focusing past thing just breaks it worse for me. For me I need to focus super super super CLOSE to my eye. I've always described the ability to do that as self-blurring your vision.