That's always my main concern as well. I see combat as a means to add some tension to a story, not an end in itself. Reasonable people of all kind should *always* avoid a lethal fight where that's possible without compromising their goals too much, because that's how everyone but a madman actually behaves. There are three situations where you fight (not counting a brawl): if it's unavoidable, if your goal appears to be worth risking your life, or if you're so powerful compared to the enemy that the outcome appears to not be in question. Real prolonged fights, most of the time, actually are the result of people underestimating the strength of the enemy. I guess we have a rather prominent RL example at the moment.
With that in mind, I prefer games where combat is a highlight and not the rule. There are quite a few persuasion situations in the EA version of BG3, and that includes main story events, so I think you actually *can* play BG3 that way. However, the question is whether you'll get enough xp that way that you can resolve combat situations where they are unavoidable or where it would be appropriate for our characters to start a fight. And because I don't know that, I'll do some min-maxing.
BG3 is a game where we are trying to stop the followers of the gods of death and murder from sacrificing hundreds or thousands of people to empower their deities. This isn't going to be a diplomatic adventure. No one was going to convince Hitler to "be chill about the whole concentration camps thing, my dude".
It sounds like you would be interested in a political intrigue setting where the occasional assassin has to be stopped to protect your delegation, but most things are accomplished through espionage and conversation.
That sounds like a fun game for sure, but it is far more niche than a AAA game can be afford to be while still making money.
I appreciate you planning to min-max to account for that difference though. It's good to see that people can appreciate the game for what it is rather than expecting it to be something it's not.
There is usually a ton of diplomacy and intrigue in these games, even if the main bad guy has to be fought. You ally with factions, convince street gangs to leave you alone, help someone out to gain a specific piece of information and so on. What I want is for that to matter, and for the game to regard diplomacy or intimidation as an equally valid approach where it appears plausible, in terms of xp. I do not demand it to be plausible all the time, just to apply some damn realism. You might get into countless brawls in a day depending on where you are, but people do not enter lethal fights lightly.