We have two small kids, our Highlander is by far a better every day vehicle than the 4runner. But the 4runner is more fun !
A third kid would be the breaking point, and minivan time. Or full size SUV. Having said that I rode in the 3rd row of our friends 2021 Yukon Denali XL and it was horrible! They've had tons of problems with it too.
PS let me expand by saying that the 4runner is the bomb, great resale, nice rugged look, rides fine, stone cold reliable, decent gas mileage for what it is. The Highlander is a great soccer-mom type vehicle, great on road trips, great grocery getter. I can drive the 4runner hour upon hour on the highway no problem but some complain about it's manners. The Highlander feels like more like planted and tight.
2nd row of the Highlander can move forward and back quite a good distance, and can give unreal legroom slid back if nobody is in the 3rd row, and great 3rd row legroom if you want to slide the 2nd row up. My 4runner has sub-par 2nd row legroom especially if the front driver and passenger are taller and like to ride dirty slid back and leaned back (meant to be kinda funny in an immature way, my favorite).
Final PS, that Nighshade color is nice! And bring back Shoreline Blue!