I am sorry you are having so much trouble with your blade holder on the Ryobi. I have a DeWalt and really like the blade holders it has. I did find that if I only tighten my blades till quite snug, but not so tight it'd take pliers to undo it, that the holders tend to work better and last longer. I guess you can tighten too tight or not tight enough. LOL...I'm not trying to confuse you, but it does make sense. Have you taken the holder screw out and sanded it to see if it'll hold better? I've done that a few times. Let us know what you decide and if you come up with an idea that works for your Ryobi.
Hope to see you in the chatroom again soon..