If you have found this place like me and if you're struggling with nested menus in MUI, especially around proper keyboard navigation and accessibility, I ran into the same issues.
Most shared demos or existing libraries have some kind of small issue with focus management or keyboard navigation. I spend an adequate time to solve these issues with better-mui-menu. After dealing with all the edge cases and quirks, I decided to share it. Hope it helps you until MUI comes with a solution to this: https://www.npmjs.com/package/better-mui-menu

If you have found this place like me and if you're struggling with nested menus in MUI, especially around proper keyboard navigation and accessibility, I ran into the same issues.
Most shared demos or existing libraries have some kind of small issue with focus management or keyboard navigation. I spend an adequate time to solve these issues with better-mui-menu. After dealing with all the edge cases and quirks, I decided to share it. Hope it helps you until MUI comes with a solution to this: https://www.npmjs.com/package/better-mui-menu