It is not meant to be played as Lone Wolf although you still can. One of the best things of the DnD Classes is that all are viable in some way but none excells at everything. High AC enemies are a weakness of the classes you describe. You have to build around them by having a good party to complement you and make up for weaknesses or use sub classes like eldritch knight or feats that give you certain spells that might come in handy if you want to trade off specialization for versatility. DnD 5e gives you all the means.
I get how party composition works. You are missing my point.
In 5e misses are ok, they do not feel like a slog because you often don't spend that much time in combat any way.
In BG3 I'd say 80%+ of your time is devoted to combat. So having even a single member of your party miss that 50% of the time, at least at early levels, is very frustrating. Sure, once you up your Str/Dex it will get better, but for the first 3 levels your fighter is just a machine for shoving off cliffs?