I would say most of the mainstream Xiaomi/Poco phones are the most repairable - Not because they are easy to repair, but because there is a extremely good supply of parts both in their authorized service centers and open market at extremely reasonable rates. Of all the phones I have owned, these have been the easiest to service. They are like the maruti of smartphones !
As much as I love the fairphone, What's the point in buying an extremely serviceable phone if the parts take ages to come and cost $$$$
I have an hp elitebook with an ifixit score of 10/10, but parts availability is atrocious in india, and it has been sitting dead waiting for parts.