I think the consensus is that most rooms don’t need much acoustical treatment as long as there is a furnished room.
All the listening rooms we see with all the really really fancy gear only have all the really really fancy gear in them. It’s ridiculous it’s not normal.
I also think the consensus is diffusers make more sense than absorption panels because they scatter the waves and reduce lots of the reverberation affect. But they don’t diminish and absorb all the detail. So if only the world would create better looking diffuser panels then the crap they have now. Some look nice but many of the so-called absorption diffuser combo panels which are ridiculous look horrifying, with a few exceptions here and there.
I would buy diffuser panels in a minute if they looked nicer, but frankly they are a pain in the ass to buy because the marketing and the availability and the design and the size is so difficult to deal with with on all those damn websites that do a terrible job marketing this product. And the ease at which you can mount them on the wall is absolutely horrifying, it could be a lot easier.