You can a also play with a low AC if you want a better challenge. Even at BG3 high levels (Like 12) with 5e bounded accuracy you should not have AC's in the high 20s - the game system is not designed around that. Look up stats of high levels enemies f you don't believe that. In my case my monk character had an end game average 22AC - without using any monk abilities or really overpowered stuff . That was enough that they still manged to avoid being hit in most case. Likewise, your to hit bonus should be bounded in the same way...if its not, the system is not really following the 5e design philosophy. Sadly Larian threw balance out the window so that further messes things up.
In 5e AC is overpowered and works against magic spells that need to hit. Which is daft but a simplification because players apparently don't like to worry about different kinds of AC... in 3.5/3e you had "touch AC" which was all about dexterity and was usually way, way less - certainly a fighter in platemail would have been easy prey for any touch based spell attack (any spell with an attack roll). in 5e - especially with Larian's overpowered items and broken AC stacking from some sources - you can get such a high AC that almost every attack (physical or magic targeting) misses. Of course, even in that case, a smart DM would adapt and drop AoE spells on you, or things like magic missile that never miss...but Larian is not a good DM.
