Ash and Goh are treated differently based on their 2 goals. Goh has one legendary, even then its roaming, and Ash still has powerhouse Pokémon; Sirfetch'd, Gengar, Dracovish, Lucario and Dragonite. Goh still has not caught a pseudo. Ash also already has hos reserves, which as we have seen, can be called back, including a mythical and ultra beast.
Ash's main accomplishments come in the opponents he faces and overcomes, and while Ash has captured powerful Pokémon, we have seen the reverse situation with Goh facing other trainers less often.
Ignoring the fact that the 2's progress is meant to be evaluated in different ways is missing the whole reason for the differences in their characters. Otherwise we should be asking why Goh isn't in the PWC and defeating high level trainers.