I've bonded with the sidekicks more than the main party members in PoE2 just because of how the game makes you recruit them out of the blue
Konstanten is the best example here, at first he looks like a random ass NPC in a brothel you can pay for services but when you delve into his personal feelings about the job you find out he's just really bored and wants more excitement.
That's reason enough for you to recruit him into the team but what got me was you're not putting him in the crew to work on your ship. You're putting him on the front lines as a full fledged party member. My jaw literally dropped when I found this out and he's been one of my favorites on the team since then.
(Had a similar experience with Grieving Mother in the previous game. "Oh, this grieving mother might have a quest for me. Wait, why is her backstory so detailed? Why is she asking to join my pa--SHE'S A PLAYABLE CHARACTER!?!?")
I don't know why but I absolutely love this about the game. Also Konstanten is best bro