YMMV. It's been more than a decade since I played the games but I have distinct memories of dying scores of times in the early game, from the very first encounter you have outside Candlekeep and many, many times in events you just wander into while exploring. It might be (somewhat) authentic to the AD&D experience to die in random encounters that pop up, but ultimately I don't care about the authenticity of the experience or accuracy of the game rules when that detracts from progressing through game/story content.
That's the early-game DnD experience I was talking about. Yes, it sucks. And is a very valid criticism for ALL editions of D&D as well as by-the-books implementations of it.
But after that, it sounds to me like you just wanted to proceed through content without being challenged in the way these games are challenging you.
NWN got around the early game DnD experience simply by increasing character HP. A character that would have died by-the-rules through a critical hit due to having only 6hp would survive in NWN due to the flat hp bonus each character is given.
A crude solution, but it does its job.
By the time I got to the Kobold Mines I'd already used a character trainer to max out stats, and even then the game was hard, and this was when I was young enough that I would spend countless hours grinding out Nintendo-hard games.
That's because they are different kinds of difficult. Aimed at very different mindsets.
"Nintendo-hard games" (I like the naming!) really require tenacity and physical player skill (reflexes, mostly). You can stubbornly approach a situation in the same manner you did the last 10 times and you will eventually succeed, simply because your reflexes and mastery of game controls have improved. In a way, that also requires patience.
I've been there and done that, too.
Nowadays, I loathe games that test my patience, couldn't play games like that anymore. I lack the patience to git gud in a game's physical controls.
In tactical/strategy games (especially the RPG variant), tenacity and physical player skill are practically useless. You cannot grind these games. Patience won't get you very far, either.
Instead, you need to understand the system, the encounter situation, play tactically and with a cool head. It's much more cerebral. Every encounter has at least one solution (usually much more), it's a bit puzzle-like in that sense. Requiring understanding more than patience (though I guess you could blindly go through different approaches until one works).
Approach the same situation in the same manner and you will just die again, no matter how often you do it.
Undoubtedly leading to frustration eventually - but that's not the game's fault, and it's definitely not unfair.
In your example, the fact that you boosted your stats and you STILL had a very hard time is very telling: It wasn't the stats that were the problem, it was your approach.
Again, been there, done that. Pretty sure I went through the game with a bunch of "illegally" buffed characters as well when I was 13 or 14 or so. What was the name of that tool? BGKeeper or something like that?
But eventually I opted for the intended approach and that stuck with me since