It's difficult. I think Uncharted 2 just edges it for me over Uncharted 4. Both were excellent games. I liked 3 a lot more than most people did, and was just ok with the first - dated by the time I played it. I never played Golden Abyss but apparently it wasn't anything special. I quite liked The Lost Legacy. My overall list is probably this:
Uncharted 2
Uncharted 4
Uncharted 3
Uncharted: The Lost Legacy
Uncharted
However 2 & 4 are very close and 3 & TLL are very close also.