Metacritic rated Pokémon Pokopia as the highest-rated Pokémon game on its site.
The distinction comes from aggregated critic scores rather than a single publication's review. The article says Pokopia received generally favorable reviews and became the highest-rated Pokémon game on Metacritic at the time described.
Other outlets also responded positively. OpenCritic reported that 98 percent of critics recommended the game, while four Famitsu critics gave it a combined score of 39 out of 40.
These figures should not be confused with one another. Metacritic and OpenCritic are separate review aggregators, and Famitsu publishes its own magazine review scores. The question asks specifically for the site associated with the highest-rated Pokémon claim.