I would like to use, of course, SSO 3 for MacOS, but..

In SAP GUI for JAVA (MacOS), you can create a shortcut and save your login and password.
It’s convenient to drag it into the dock for a quick start:

1. Right-click in the SAP GUI on the desired system > Save Connection Data as Document, save it somewhere
2. Find this file and open it with a text editor
3. Add data to the connection string (enter your user= and pass=):
   conn=/H/hostname.domain.com/S/3200&expert=true&user=ikostylev&pass=MYPASS&clnt=100
4. Save, drag the file to the dock on the right side
   It is not safe to store passwords in clear text, but if you really need to, you can.

For security, encrypt the disk by enabling FileVault.