He and primrose both say they're getting into personal business... but if you insist, just stay out of my way.
I think people are getting a bit too hung up on how there are protagonists that don't want others in their business, and not thinking about the core of their stories; that however they start, they admit through circumstance that it's a journey they can't handle alone.
think about it! just play as therion, and think about why he'd decide to help some doof like Alfyn. you can see on the world map that every character's chapter 2 destination has a recommended level at least 4 times what they have after they start. if he decided to try for the gems now, he'd never make it, and he knows this.
despite his dislike of working in a group, he knows he has to at least tolerate other accomplices if he wants to get those gems and free himself of shame. this is a similar take to any other character, they may start alone, but they aren't dumb, they know they need help to finish their journey.
so yeah, the beginning of these partnerships aren't unique, they are all just opportunities to play their stories in a single playthrough, and get access to another party member. but a truly powerful journey isn't made memorable by the details of the beginning or the end, but the journey itself.
so I understand how so many feel about the bare interactions of the beginning, but I urge you guys to consider and understand the confirmation of quality interactions after this point. maybe I'm a fool, but my experiences with this game have given me hope for the full release, and I hope it ends up meeting your expectations, too.