I hope as we go into new areas just once in a while, to keep it refreshing, I'd love to run into a group of enemies that would have been troublesome at levels 1, 2,3, 4 etc. but now I get to feel like I've become a total badass by crushing them later on. Obviously the game needs to be challenging and enemies should scale, all I'm saying is once in a while getting that sensation of how powerful we've become would also be nice and is missing from most modern RPGs. Like every now and then we should just be one shotting fools.
Maybe it's due to the limited scope of Act 1, but I feel like, with the non-linear nature of RPGs like BG3, you'll naturally have more and more encounters like this as the game goes on. This can be roughly measured as, the ratio of the amount of XP required for a party to have a reasonable chance of beating an encounter of a given difficulty, over the total amount of XP available to the party through encounters of lower difficulties. This ratio will tend to get lower as the game progresses, although the level cap in EA obscures this somewhat for now. Any encounter in Act 1 can necessarily be beaten by level 4, but there is enough XP available to reach level 5(which is nearly 3x as much as level 4). If you had the opportunity to stomp some Act 1 encounters at level 5, would you feel more like a badass?
I suppose one of the downsides to us being stuck with Act 1, is that those with multiple playthroughs already know where everything is. We know what areas contain the most challenging fights. But the more widely branching paths that are presented, the greater the chance to have encounters with enemies below our level as the map is fully explored.
Part of this can also be due to one's exploration style. If your map looks like slowly expanding completely filled areas, your encounters will tend to more closely track your level. You won't often encounter things far above, or things far below your level. If your map fills in more like a scribble across a page, charging deep into the unexplored, changing course only when you can't progress, you'll have a greater mix of difficult fights and easy fights. That could be a reason why I don't think there's much to be done here as you do. I'm definitely the latter style, but I recognize that not everyone plays like me, or wants to.
In my first playthrough, I found my way into the Underdark very shortly after getting invisibility at level 3, sneaking through the Goblin Camp and Shattered Sanctum. I leveraged Glut heavily, but I got to level 4 before heading to the surface again. Most of the main story arc was still left for me to do, and Risen Road, Waukeen's Rest, Mountain Pass, Fetid Bog and Whispering Depths were still entirely unexplored. I'm guessing that made them significantly easier than they would have been had I visited things in a different order.