I made a quick test, I dont know if webgpu works on exports yet so I only used webgl. The cpu usage for Top Down View and static lights are REALLY LOW even without baking, like 1% usage. Fps View went up but still really good! I will try webgpu after I rebuild my level.
https://cristo1.itch.io/test-3d-object here is link
(also its a really low poly model with around 400 tri with the buildings only having probably 20 each) And if u bake at just the right angle, you wont be able to see the triangles at all, you can tell from some of the sides of the buildings. so it can work with low poly fine with the perfect setting and angle.