By the time they are 3 or 4 things will be much, much easier. In fact, in many ways easier than two kids further apart in age. They can be in the same school, the same clothes, keep each other entertained, etc.
I’m sorry but you have no idea that’s the case.
My boys are almost 3. In the last 12 months one has been diagnosed with a visual impairment, brain damage, a metabolic disorder, potentially a genetic disorder, and ASD. His twin was then also diagnosed with ASD.
Everyone told me it would get easier too. It hasn’t. They may well not be able to go to the same school, they certainly don’t keep each other entertained, they often won’t eat the same food...
I know lots of twins around the same age as mine. Some are finding things getting easier but others are finding things getting much harder - speech delays, developmental delays, physical health issues etc. There are no guarantees. This situation needs solving now because if this were me I’d have had a complete breakdown.
People are talking about kids being able to climb stairs at this age - not four storeys, and getting up is even less of an issue than getting down!
You need to move, like yesterday. Not necessarily to wales although I too would be pushing to try that if I had family support there given you don’t have it now.