Legends Arceus is a masterpiece & SV will be too!
Simple: They hate Goh and are apalled Goh would get the 'honour' of having Gary be a rival even if it makes perfect sense writing wise and just want everything to be for AshThat's exactly what Gary's role is, you're just seemingly bothered by Go. I also don't know why you keep bringing up the fillers where Go captures a pokemon, those are not the Project Mew missions. You literally seem to not comprehend his catching goal and the Project Mew missions are two different things.
And Gary and Ash have had a lot of focus together too.