To design a macOS application, use SetToolTip in menuItemImage or menuItemButton, how to change tooltip font size?

The DDC/CI application can work well on MacbookPro/Mac Pro (Big Sur), but it doesn't work on M1 Mac (both macOS 11.0.1 and 11.1). M1’s graphics card is Apple, not Intel or AMD. Does this incompatible issue relate with new graphics card or kernel change? Any alternative solution for M1?

Hi, I'm developing a cocoa application that need to run a script when user enter login screen. I'm thinking of using a daemon plist to to the job, but I don't know when to fire the script. Do anyone know how to detect when Mac enter login page? Thanks in advance.