I think focus for the boys has been pretty equal so far. Ash has had plenty of episodes centered on him regarding the PWC, captures, and recently the jealousy episode with Pikachu. I think it only feels like Go is getting more focus due to him getting the most captures
To be fair you can say the same thing about Ash's current Pokémon besides Pikachu and RioluMost of his Pokémon still come off as robots or background filler.
You could definitely can made same thing can be said for Travel friend of Satoshi worst way tho they don't even get more Pokemon......not only just 2 or 3 of them !To be fair you can say the same thing about Ash's current Pokémon besides Pikachu and Riolu