Hey, Aimee,
It is very very hard to find a comfy enough travel stroller for a larger toddler. Especially that tall backrest and the flimsiness - I mean, these are the smallest buggies in the world, so all got smaller on them, and it' hard to find a sturdy one (they are usually the more expensive ones). I will, thus, suggest the Joolz Aer and the Bugaboo Butterfly as the tallest-seatbacked options, and also check the Recaro Lexa (nice enough space) or the Ergobaby Metro+ sturdy.
Also check my newest top ultracompacts 2023 article just to inspire yourself. All of the suggested strollers are in it, heh :-)