If you're looking for a vanilla+ style mod rather than some of the more dramatic overhaul, I'd suggest Krastorio 2. It adds 3 new science packs and some tweaks along the way that fit into the vanilla feel pretty well for me.

It does tweak nuclear a little, giving you a way to use reprocessing side projects for fusion power near the later part of the tech tree.

In terms of circuits, the one area in which I always use them is to control oil refining so I didn't end up capping on heavy/light oil but also didn't turn it all into petrol and leave myself without the resources to make lubricant or rocket fuel.

Space Exploration pretty much forces you to use circuits too in controllijy what goes to your space stations/other planets but it's a long mod with most of the content basically starting after a full vanilla playthrough