And yes, there is such a thing as the "best" party in BG3. It is fighter, cleric, rogue, wizard. That is the party everyone should always play with. Deviate from this party and you are shooting yourself in the foot.
For me this is a very bad and not fun party. I am assuming this is the "traditional" version with fighter as melee, rogue as mostly melee, and cleric melee when not healing? I do not enjoy this playstyle at all, the enemies need to die before they get in melee range. Tried to make myself like it, even having just one melee (fighter) but it didn't work.
I find fighter completely useless because they do not get crowd control spells like ranger does, and the enemies tend to die before they get a hit in if I play them as melee. Rogue I always play ranged but even they are unnecessary because anyone can pick locks. Cleric healing can be a good thing depending on if I screw up spell placement, but I always keep them ranged.
My best and favourite party (custom) so far was ranger, rogue, sorcerer, wizard. With vanilla companions it was ranger, rogue, wizard, cleric (because I always forget that short rests are a thing for warlock.) Probably at higher difficulties I will play ranger, sorcerer, wizard (or another sorcerer,) cleric, since the ranger will pick locks and scout. All stealthy, especially for traveling and ambushes, and ranged with strategic use of crowd control spells and positioning. A 4 sorcerer party would probably be just as fun and efficient, but I would miss Spike Growth and Ensnaring Strike too much.
