Goh already understands that certain Pokémon have roles that they need to carry out, we saw it with Suicune. The writers also aren't going to have Goh give up his dream to catch Pokémon. We have been shown that Goh cares for and works to understand his Pokémon, given the PV, it seems like this arc will be about him becoming more serious/ stronger.
We are not on day 2, and catching a legendary is not the Wallace equivalent of Goh's dream, he wants to catch all Pokémon.
"Didn't" catch Zapdos, caught an already defeated Eternatus which was then sealed, befriended Suicune who is still roaming, and JN is just less stingy with evolutions overall, don't forget Ash's Dragonite evolved because it wanted arms.
Suicune is 1/80 of all legendary and mythical Pokémon. Goh didn't defeat it and he doesn't have it on hand, meaning that capture brings him no closer to getting the other 79, most of which are just as strong or stronger, not to mention every other Pokémon species he hasn't caught.
You are all acting like he is about to complete his goal when he spends most episodes catching Pidgey's and Pansear's.
1) When Ash battled and defeated a Wild Articuno, he barely managed to do this in the Battle Frontier arc, and even that was with his Charizard which was his most experienced Pokemon at the time. Here we have Goh damage it enough to almost capture it, without having a fraction of Ash's experience. Now even if Articuno was controlled by Nolan who is a very good trainer, one can also argue Ash himself was a veteran trainer who was very experienced. So this advantage Articuno gets evens out which still makes Goh's accomplish silly.
2) Legendary pokemon have in general shown to be much stronger than the average pokemon. Most trainers in possession of Legendary Pokemon have been shown to be strong battlers with a decent level of competence. Tobias, Brandon, the Elite Nurse Joy who worked for the inspection agency etc. Plus to add to that, special Legendary Pokemon (Have shown to possess a level of strength even above that of a regional champion). Eternatus was stronger than Leon. They could've simply had it fly away, but no, Goh had to get a cheap capture. It's not "Sealed". It is simply in a Pokeball belonging to Goh and is locked up. Goh could very well go and retrieve that Pokeball and use it if he pleases. Plus, Goh has no business even owning a Legendary Pokemon give n his level of competence as a trainer.
3) So what if he "Befriended Suicune"? There have been many cases where Ash befriends regular Pokemon who then challenged Ash to a battle and only then went along with him once Ash proved himself worthy. Given how Legendary Pokemon are known to be much stronger than the average Pokemon and possess a great deal of strength, it would've made more sense for the Legendary Pokemon to give Goh and opportunity to battle and Catch it and during the course of which, have Goh realize that he needs to get stronger as a trainer if he wants to capture Legendary Pokemon.
4) So what if Suicune is 1 of 80 legendaries? There are over 800 other regular Pokemon for Goh to capture. There are what? 24 elite four members and Ash never beat 1 for years. He never even won a Regional League until Alola. As a matter of fact, he didn't even reach the Finals until Kalos. They could still have Goh battle and capture regular Pokemon and maybe have him try to capture the legendaries once he completes the Pokedex of that specific region. Maybe capture all Pokemon in Johto and then try to hunt down the legendary dogs?
As for the evolution part, I sort of agree. That said, Journeys is doing a horrible job of Indicating Ash is superior to Goh in battle.
Like for example, Ash didn't need "Team Rock and Goh's help" to battle Zapdos in a raid battle. Ash and Pikachu have beaten multiple legendaries in the past. Also, even in the Mewtwo battle, Cinderace was shown to be stronger than Pikachu which was again frustrating. Goh had no business battling Mewtwo. They could've very well had Goh chase mew and allow Ash to battle Mewtwo himself.