I travel solo frequently with my three kids and have done when they were tiny - I’d three aged 3&under. The older two are school age now so it’s easier.
As an airport stanstead isn’t unusual for a UK airport. Check in at stanstead is easy (drop off and parking are relatively close to departures). I love that oversized luggage is also close to the departure gates (in some airports you have to walk 5-10 mins in the wrong direction). Security are often great with babies and liquids, and have been kind to mine when they haven’t wanted to walk through the machines without me. It’s a long airport to navigate but corridors are wide enough that I’ve managed it with two single yo-yos.
The gates are grim and it’s the lack of air bridges. However, even when air bridges exit in the uk - often it can be hard to fold the buggy at the “narrow” end before the plane especially if everyone is focused on getting onboard.
With Ryanair, though they don’t technically prioritise families. If you ask them for help as they are setting up they often will. I’ll stand towards the front (priority for the buggy to come onboard) and usually have one case (checked in) for all of us with backpacks each too. Kids carry their backpacks once the buggy is folded down. I ask strangers to hold their hands on the steps and someone else to take the buggy. 99% of the time people are polite respectful and willing to assist.
However international airports are often a dream comparably! With children’s play areas and family swift lanes (for security, passport control), much clearer signage and often free mobility aids (several I’m in have free buggs or transport chairs after the gate to use till baggage, then park and they’ll return - others have areas to rest between gates). Even in terms of food offerings before boarding (ie having chairs that are clean, space between tables to navigate easily).
A huge fear of mine traveling from the UK is the lack of notice before gate info. Little legs just don’t walk fast enough and I’ve often had to put two into a buggy, carry the third and run (which is NOT safe). I typically rely on knowledge of which airline tends to fly from which space/gate area. But often the changes announced then only allocate for a mobile adults walking time! That v v rarely happens abroad.
I always fear navigating stanstead (and Heathrow and gatwick too) with mobility difficulties. Know my parent finds them very hard to manage (joint pain). When I traveled a few days post c section (with the baby’s) I used mobility assistance and wouldn’t have managed it without that. That being said, the access to board the plane for wheelchair users at stanstead is a specialist (and small) podium type lifting machine (ie it’s not a building lift). And you do see people dropped to gate who also have to use the stairs at departure gates and up to the airplane.
Im aware the travel I do now, won’t be feasible in old age - and that saddens me. It shouldn’t be that way.