"Did Pokemon benefit from the Switch effect or did the shift to DLC expansions just eat up the 3rd version/sequel sales?"
Ummmm... that's a really weird question, because those two options don't seem to in any way contradict each other. Pokemon seems clearly to be selling more. I don't see why the fact that a chunk of the sales are DLC should impact things.
I think it's hard to argue Pokemon is selling better. In addition to the games listed, you have Pokemon Pearl/Diamond, Lets GO, and Arceus selling around 15 million each. If you look at sales per sku, or per year, I'm pretty sure they're selling more games even before accounting for DLC, and when you throw that in they're selling waaaaaay more content. The fact that they're not using the same exact model as they did in the past shouldn't really matter.