Since most of the neighborhood is located to the west of this project, and since that's where most of the blazing sunlight will be coming from, they'll still have good sunlight. Also, there is no street between this tower and the one next to it, just an alley.
As for everything east of this project, that area right now is a no man's land anyway. I've lived in Austin my whole life, and I only visited that part of downtown one time in the early 90s before all of these towers started. That was to visit the architect son of a friend of the family who was restoring a house there. At the time, I think they were planning on moving into it, but they've since turned it into a restaurant from what read about it the last time. He almost became family. At the time his dad was dating my aunt.
You can read up on it here.
https://atxwoman.com/behind-counter-lestelle-house/
Streetview.
https://www.google.com/maps/uv?hl=en...px8wDXoECAgQCw