Yeah, you will always end up better off just buying a better GPU instead of faster RAM, it doesn't make a lot of sense given the price difference. And if you really are running a 1080Ti or so, then why bother optimizing for 1080p anyway? It will run fine.
On my board in general yes, that is correct (or it was last time I checked). But with new UEFI versions, updated microcode and more testing on all sides, that recommendations list is changing a lot currently.