Depends on how the back story is. In Dos 2 my first run was with a custom char, now I'm playing with Sebille and I found it engaging because I like her story line, in a future I'll play as Lhose.

In BG3 for now I would be interested in Shadowheart's and Astarion's story lines, I wait to see if they'll add more companions/origin characters, I'm somehow intrigued by the high druid.