- Edited
Pepe LeFrits stats like this don't make sense to put much thought into. GKs for lesser teams will obviously have more saves.
Shot-stopping is fairly well measured by the difference between post-shot xG (taking quality of the shot into consideration, i.e. shots off target will have an xG of zero) and goals. Raya saved 5 more than he should statistically be expected to. Alisson 10. Ramsdale should've saved 2 more. There are slight differences in calculations, just like in xG for teams. As you see in Clrnc's post above, Orbinho has Alisson as 8.5 instead of 10, which is from Fbref.
The thinking behind Ramsdale is clearly that what he does with the ball compensates for his below average shot-stopping, and probably that his shot-stopping will improve. Maybe they've become unsure of the latter. Unicorns like Alisson who excels at both things don't grow on trees, but Raya seems very capable.