Eyyyyy, if you found that #firefox's auto-Picture-in-Picture feature (it's in Firefox Labs in about:preferences) was a bit too aggressive when it first released, then today's release in Firefox 133 might be a better fit: we've made it so that there's a higher likelihood that when we auto-PiP, it's for a video you actually care about, rather than the first video on the page.
Try it out!