Did you check Swiss air? My kids are flying to Prague and Swiss came in between Lufthansa and Aeroflot. Another airline that was reasonable was SAS.
My DD had a problem with Aeroflot about a dozen years ago when traveling with a high school student group that had booked a flight to Moscow. Probably about 12-15 in the group, including adult chaperone. Aeroflot overbooked the flight, and rather than bumping a single passenger or couple, wanted to bump from the group. It was a connecting flight out of Los Angeles - the group had flown in together from SF. So there they were, in a different city from where they all lived, not being allowed to board the full group on the plane. Not only that, at the time Aeroflot did not have daily flights, so it would be 2 days before the next flight.Obviously they couldn’t leave a kid behind, or have the kids sent off without the adult who was leading the group.
It ended up that Aeroflot paid for the entire group to spend 2 nights in an airport hotel in LA, and the kids had a good time there, even though that meant that their planned time in Moscow was cut short. Airlines do overbook and flights get cancelled, but I do think another airline would have handled things differently.
Update! I decided to book a flight with Air Canada going to Prague and Lufthansa going back. A bit pricier but no long stop at Moscow.
Congrats. As I said, I would have no issues with Aeroflot, but I would pay $500 to avoid SVO and the Russian equivalent of the CBP and TSA (whatever they are called).
(The only time I purposely booked travel through SVO was when we needed to import our cats. All other transit countries required microchipping them and a rabies titer done by a certified lab… that was not going to happen in the country where kid was.)