How to enlarge/reduce size of window like the rectangle app?

Hello, new to BTT here! really appreciate everything you guys had done so far. Just wondering, is it possible for me to enlarge/reduce window size using any custom resize information? Been trying to tinker with it but couldnt figure how to make it work like rectangle's make smaller and make larger function ( ctrl + option + -/+ )

Here is a simple example how you can achieve this with the "Custom Move / Resize" action: