I think the rendering pipeline for D3 is actually the hard/strange part, and to be honest, the less-valuable part too (can be swapped with React). The rest of the API is great. The new strange, unordered observablehq examples with extra DSL interspersed aren't helping.

I agree a LOT with the comment below.

D3.js comes with function that modify the DOM. This is react job too. So using both together can be a challenge.