I think the thing that gets in my craw mechanically is that as you point out, a non-standard wizard will always be behind from the start of a campaign to pretty much the end, which few campaigns reach anyway.
This says it all.
People want to min/max, not for the character role, but because they don't want to feel like they're behind. It's not the role playing so much as it's the roll playing.
You say that like the to aren't inherently connected. They are. Pretend all you want but the stats and roleplaying are inherently linked. Not just for combat, but for everything. Acknowledging that isn't min-maxing. I find the idea of class dipping like sorcadin or sorlocks pointless and tedious. I don't use charts or plan builds. My favorite class and subclass are archfey pact of the blade warlock, which based on what I've been able to learn in D&D circles is considered a weak subclass and pact boon. I like it because I think fairies and swords are cool. Again, there's a difference between min-maxing and being aware of the numbers and how they affect things.
As to the people commenting on my outlier spiel, I admit I don't know Forgotten Realms lore. All I know of it comes from the player's guide, a bit of the DM manual and a bit of Xanathar's guide. So maybe that's why I don't hold much regard for the lore. I've been under the impression for years that the intent, explicit or not from the core rules is that you're "meant" to create your own setting, and all the flavour stuff is there just as a baseline. And it's a baseline that's really never grabbed me if I'm honest.
I'm not against min/maxing. I'm not against role-playing. And I agree that both can be done at the same time.
That said, I do think they come from different places. I say that as someone who has a strong desire to do both. It's rare that I don't try to optimize my character. If I decide to play a wizard, one of the first things I think is that I need a high intelligence to be good at what I'm doing, and I adjust my stats accordingly. And I'll sketch out for myself a personality and identity based on all of that.
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As opposed to saying I want to play this character who happens to be a wizard because, say, his family pushed him into his apprenticeship. They wanted the best for him, but he never enjoyed it because it was so hard for him. And he always felt like an underachiever because his parents wanted him to be smarter than he was. So he struggled and he struggled, and eventually he became a first level wizard.
But maybe he always had more of an interest in physical pursuits. He wanted to go out hunting with his friends, using bows, training with the militia.
So now I have a character with a 12 Int and maybe a 14 Str. As the character progresses, maybe he takes a feat learning how to use weapons instead of increasing his Int.
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These are two very different approaches. Both can be fun. In one, my character excels at what he does. In the other, the game becomes more challenging, and I really have to think about how I'm going to overcome obstacles. I also get to enjoy seeing my character adapt and grow in the world, rather than just pursuing the road to excellence.
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These two styles don't always get along at the table. The min/maxer can easily get frustrated because the other player isn't carrying their weight effectively. And the non-min/max player can get upset because "it's not all about the numbers, Chad! Stop telling me what feat to get."