I'd consider myself a bit of both. I like making my characters as just that; characters. I can never truly get away from it still being me at its core, since that's just the perspective I'm stuck with, but I like to change it up from time to time.
Once I have an idea of what sort of character I want to play, I start to look at gameplay and how to optimize that character within the system I'm playing with. Let's say I'm playing a character with training as an enforcer for a Thieves Guild, trained to use light armor and twin blades. Probably Criminal as my character background and would lean towards selfserving choices, but they would never side with the chaotic and untrustworthy goblins. Is a lightly armored dual wielder the most optimal character to play in BG3? Probably not, but I'm willing to live with that since it is decent enough.
I have 3 main options for what class I want to use in BG3 EA; Fighter, Ranger and Rogue. Each of these have pros and cons compared to one another in the current matchup and I happen to like all three. Let's say I decide on the consistency of Rogue over the more resource dependent Fighter and Ranger.
So far, so easy. All three classes are mechanically strong as far as two weapon fighting characters go. But then I hit level 3 and have to make a choice between Thief and Arcane Trickster. My character's background makes more sense with Thief.... but Thief isn't that appealing mechanically. It used to be when Rogues still got two weapon style as a hidden bonus for some reason, but that has been patched out a long time ago and my bonus action attack is now just a 1d6, instead of 1d6+3. So having 2 bonus actions isn't as big a deal.
Arcane Trickster, on the other hand, is very mechanically strong. Getting access to Wizard cantrips and spells, even from a limited selection, is a huge boon both in an out of combat. Having an additional character to cover spells like Feather Fall and Mage Hand is great for letting Gale focus on other things, while cantrips like Blade Ward can be extremely useful if i need to lock down a position for a turn. Or just survive.
Given the difference in how useful Thief and Trickster is, it is unlikely that I'll ever play a Thief for long. The difference in optimization is just too great.