WetGeek it would be great to know how to undo this last fix
I found out about the eopkg history -t
command from the help center, and was able to get rid of this version of mesalib. I'm not sure I could have lasted too much longer using Firefox as a substitute for Vivaldi. If it helps with the debugging, I've tried both Wayland (my default) and also X11, and Vivaldi was unusable on both.
I hope this can soon be actually fixed in the repository, so it will be safe to apply the next update. Actually, I'm glad I finally needed to learn how to restore a previous version using eopkg. It's a very useful thing to know, and very easy to do.