I would think the option to enable a 6 person party in the settings would be best, keeping the default max at 4. I say this because I prefer playing with a smaller party personally. My fiancé and I play 2 characters each. That seems perfect for role playing our own Tav and having a side character to role play as they should be playing based on their character background.
However, when playing DOS / DOSII, we never went the Lone Wolf route. Even though we talked about it many time, every playthrough we ended up deciding to pick up a companion.
Similarly, I'm playing through BG and BG2 right now and guess what...I'm playing alone with a party of 6. Why? Because it's the default and I feel like that's the intended party size for the game, and that I'll miss out if I leave empty slots.
With BG3 though, we play to play through numerous times. The ONLY things that will keep us playing after the first time through is playing a new class Tav, and having different companions.
We've already run through all of the existing companions, multiple times. Even now, just changing Tav to a new class is pretty damn boring because since there are no random encounters, every playthrough is exactly the same, with the exception of new companion experiences.
I personally would rather play through multiple times with new, different companions than one or two times with 4+ each time.