Hi @mr slowpoke welcome to the forum!
I would use the Flip.fit() (https://gsap.com/docs/v3/Plugins/Flip/static.fit()/) function of the Flip plugin, to as the name implies fit the logo inside the other logo. Animating height is always something you want to avoid when animating, because it causes a browser repaint, which is really heavy on the browser a this will never come out right.
I'm not complete sure what it is you want to happen, but what I've done is moved to timeline (timelines are the most powerful tool in GSAP) and add the Flip.fit() animation to that timeline, now now scroll that animation plays and the rest of the page scrolls like normal. Then as soon as the animations finishes the ScrollTrigger kills it self, it sets the pink section to a height of 0 and never played again. To me this seems the best way of handling this particular animation.
Right now I've just place the .logo-text somewhere, but you can fully tweak this with CSS and then Flip.fit() will automagicly animate it to the logo up top. Hope it helps and happy tweening!
https://codepen.io/mvaneijgen/pen/YzbqWQe?editors=0010