Dichronauts by Greg Egan explores a world with two spatial and two time dimensions. As usual in his fiction, the premise is backed by math [1], but unlike his older works, I find Dichronauts too tedious and boring.
The story really is poor but the universe is so fascinating I had no problem finishing this book. I had to refer to your linked post several times during the relatively short read.
What are some of his older works that you'd recommend?
Diaspora is one I’d recommend for sure.
Honestly, I recommend all of his works. Diaspora and Permutation City are often mentioned here on HN - that's how I got started with the author - and I agree, these two stand out among the rest, at least for me, but only because I found the topics the books explore more relatable and engaging.