I'm genuinely not feeling Tav as a side-character in my play throughs.

Patch 9 play-through Tav (Baldurian noble oath of devotion paladin) was straight line consistent. The oath break near the end was a friendly fire kill because of hubris. Humbled, he re-swore the oath to take better care. Events in play defined his character, which was close enough to how I envisioned him.

When I say side plots, it's not at all in a negative sense. But in-character that's how my Tav regarded them (at least until forced to truly reckon with them).
- A noble knows they need to spend gold for power, so gifting magic items to placate Gale was highly unusual, but a cost was expected. (Baldur's Gate Patriar houses pay well for a personal wizard.)
- As a fellow warrior, my paladin recognized Lae'zel's undeniable combat prowess, so he entertained her lead, etc...

We're using 'side-quest' a bit loosely here too. We're kind of talking about story threads or different facets of main plots. With a different Tav, I pick and omit side quests.