Great news: piano tuning in 3 weeks!
Overall, I found this prelude and fugue to be more difficult than Nos. 1 and 2. With more time, I would find ways to better color the opening half of the prelude (which I consider a Romantic version of the C Major Prelude in Book 1). I feel there are better ways to think of phrasing that either play down or enhance the tenor-voice notes; the ties in the right hand also have the potential to be a bit more interesting, perhaps with embracing them as suspensions.
The fugue is generally difficult, for reasons I’ve outlined here.