Noo enables you to map a mouse button and a trackpad gesture to a set of keys.
Please note that each mouse labels their button numbers differently. You can test which button number map to a mouse button by opening a text editor, setting the mouse button to map to any key, and click on your mouse.
Noo needs the accessibility feature which you can grant the access under "Security & Privacy".
I built Noo to be used with Tip (https://github.com/tanin47/tip), and Noo is open-sourced here: https://github.com/tanin47/noo