Thank you for the information with the latch, I had the same problem and was stuck at that part years ago. Wish I knew that information about the two bars back then so I wouldn’t have had to call a locksmith. Ah well.
Seems impossible to find a "fix a door knob" where it works, but seems to have been pulled apart and can't be put back together... but evety video just involves buy another! Don't need a video for replace and install. Sigh.