Hiya, Dr. Kat!
There are actually three huge challenges to your requirements. First is the flexibility of the seat, meaning its spaciousness, really - do remember you ask for a cabin-friendly, so the smallest possible stroller type that is only meant for occasional use and travel because of its minimalist size. These are pretty much never roomy enough for a 25 kg child (I have one at home and can promise you he would look funny in a travel, ultracompact stroller). Rather take it as a thing usable up to three, maximum four years of a not-overly-large child - and look for a higher backrest in your case.
Next in line, the suspension. The maximum shock-absorbing ability possible with such a small stroller will be still a small amount of suspension, do count on that. You can't put large springs and bars on such a small model.
Lastly, the adjustable handle. There are almost none with an adjustable handle, as that makes the stroller heavier, bulkier, as any added feature does... plus, those few that do have it (like the Joie Tourist or the
) have many other features that are not ideal by far, unluckily.
Trying to prioritize here, I would either suggest a Joolz Aer here - because of its spacious seat as well as nice chassis with suspension or an ABC Design Ping (similar reasons, just a more affordable pushchair).
The Babyzen Yoyo is once for a sturdy-enough chassis but has a very short seatback and a very slanted seat (not talking about not that much suspension]]. Not much else would really be worth it here, I think - I mean, all have their pros and cons. The Chicco Goody could work (full Chicco Goody review here, but no adjustable handle and the seat back could be taller... the Easywalker Jackey sports a nice suspension but a shorter backrest as well as a slanted seat... And no strollers you or I mention as good options have an adjustable handle.
There are things to consider - a handle extension (example here), or even a larger stroller that will NOT be cabin luggage-sized but CAN be taken on board as checked luggage or as a stroller taken when you board the plane. You will absolutely need to compromise, there more so with ultra-compacts. And your partner will have to adjust - I mean, we're talking about small strollers and those won't have all the bells and whistles... And you'll be fine 😊 Really. Just look at seat size and handle height (at least 103 cm high handle should be OK).