Both of these are terrible takes on the books.
Spice is not a solution in dune in fact the whole 4th book and the end of the third are centered around forcing humanity to wean itself off spice so that it may evolve.
The central concept is that humanity must not depend on machine or drugs or complicated eugenics and must instead look inwards and improve itself by facing hardship.
In foundation (at least the start) the complicated maths is essentially there to prove that all establishments fail and survival requires constant change. Very differently from dune foundation sees technological superiority as key to this and importantly the ability for society to change in order to support the technological progress.
Even if you don't agree with the above neither book aims to "fight imperialist bullshit" if anything they both quite staunchly support the idea of a benevolent dictator controlling all.
Non horns story time ...
A long time ago I was but a young lad living in eastern Europe and I use to watch this cartoon. The actual content of this cartoon are lost to the ravages of my memory but a few things stood out, the main character had a flying board and the opening sequence was him flying through these hallways that were broken into geometric shapes and there was a big face that he flew towards.
Sometime later especially during university it became a recurring niggling idea. Did it exist or was it some dream or fantasy? I'd get enthused once in a while and try searching the depths of the net for it with no luck.
It wasn't until I had graduated and was working, close to 20 years after the fact that I found it ! The name of this show is now imprinted on my brain.