Q.Pink Butterfly Kalanchoe
Why is my Pink Butterfly so tall and lanky? And how can I get it to fill out?

Certified GKH Gardening Expert
Your plant is probably suffering from too little light. This article will help you:
https://www.gardeningknowhow.com/plant-problems/environmental/established-plants-leggy.htm
Providing more light will likely help it fill out. You could also prune it back, and even use the pruned-off portion to make a cutting and propagate the plant according to these directions:
https://www.gardeningknowhow.com/houseplants/kalanchoe/growing-kalanchoe-plants.htm