I confirm that I can run SAP GUI on Apple MacBook Air 13 M1.

• Java 1.8 from java.com
  or OpenJDK for arm:
  https://www.azul.com/downloads/zulu-community/?os=macos&architecture=arm-64-bit&package=jdk
• SAP GUI 7.5 rev 12 (Presentation - 7.70 Comp.1 Present.2 SAP GUI for Java 7.50)
• run in terminal to install SAP GUI:
  java -jar <path to PlatinGUI750MacOSXS_12.JAR>
  or
  rename PlatinGUI750MacOSXS_12.JAR to PlatinGUI750MacOSXS_12.jar and run it

P.S. Actually SAP GUI uses own java so you can download SAP GUI in dmg format and install it without java.