how to "store" a specific keyboard shortcut on mac touch bar?
Yes, you can assign custom shortcuts to the Touch Bar.

For this you need a separate application called BetterTouchTool (BTT).

With BTT installed


open the app
Click "TouchBar" to assign a TouchBar setting
Click "TouchBar Button"
Enter a Name below "Touch Bar Button Name"
Click below "Custom Keyboard Shortcut"
Press your desired key sequence