TL;DR So my overall thoughts on Thrawn Ascendancy: Chaos Rising stand at a "Good" 7.5/10. I enjoyed it and if you like Thrawn you will too. It takes a big step away from the Skywalker Saga and familiar locations of Star Wars but honestly that step is welcomed. Learning about the Chiss and the Chaos was truly fascinating. It's significantly better than Thrawn: Treason and Thrawn: Alliances, but Thrawn Ascendancy still has its share of issues.
The positives: Fresh worldbuilding and lore, strong characters and strong pacing. Unique setting.
The negatives stand: an anticlimactic villain, Thrawn's abilities are borderline repetitive and gimmicky, and a predictable ending with a cliche lead into a sequel.