My Summilux had suddenly a loose focus ring. It doesn’t really effect the precision of focusing. The reason were two loose screws under the focus ring that holds the radial fixation for the focus ring.
To fix it:
focus on 0.7m to get some room
remove the two screws holding the focus ring
move the ring towards the front
now you can see the loosen screws
I tryed to remove the backside of lens with no success. Maybe i'm a little too scared🧐 about defocusing the lens. If you tryed it and found a way, please tell me.
https://gigantoptik.com/1681
The way from the front was easy but not helpful for me.
https://yukosteel.wordpress.com/2021/06/20/disassembly-leica-summilux-m-50mm-f1-4-asph-11891-lens/
My solution was not realy professional but it works ✌️. I cut off the front tip of a suitable screwdriver and twisted it with thin pliers.
Good luck!