Found out through experience that the longer our journey from West to East (London to Tokyo) the quicker my kid adjusted to the new time zone. Once I realised this I really embraced longer transits. Travelling in the opposite direction is different, quicker the better.
I used to feel that we were “losing” a week as our first days in Tokyo at granddad’s house were such a challenge. The adjustment period feels negligible now that I build in a 10-12 Hour stopover. If your child is/children are under 7, Moscow’s Sheremetyevo airport took me by surprise as it has some quite amazing facilities (including a completely free “hostel” for kids and babies, they get a bed, the adult gets an enormous soft armchair - and it’s properly “policed” so lovely and quiet)
SVO - Bed and pillow have disposable covers - place was warm so kid refused sheets