JN146: Satoshi and Latios! | Bulbagarden

You know what would have worked? If Ash “caught” Latias, of it’s own choosing, but Ash allowed it to roam freely, like Goh’s Suicune.
Meanwhile, Latios does not wish for this, but can still be with Latias. That way, it shows Ash still has a bit to learn to befriend Pokemon like Latios, but it at least acknowledges he has come leaps and bounds when a legendary wants to be “united” with him.

Also, I have to ask a question. The whole point of this mini-series is to show that a Pokemon Master can bond with any Pokemon. But, when has Ash ever not been good at that? He has more knowledge and is wiser, but the outcome remains the same none the less - he’s just more efficient at it. He’s befriended a Zygarde and a Solgaleo, Azelf recognises him as the embodiment of Willpower, Tapu Koko acknowledges him, and I guess Lugia too…Don't you think the Mewtwo from that one Journeys episode would be a more fitting choice than Latios and Latias? A Pokemon that wishes to be excluded completely from humanity, whereas another has been shown to live near them?