Due to the high property taxes in Texas one of these types of plants doesn't really make sense being located in Texas so these types of deals are necessary but hard to pinpoint where fair is. The tax breaks seem huge in comparison to similar projects but other similar projects don't have the most sophisticated equipment in the world being installed. Property taxes include all manufacturing equipment within the facility and not just the facility itself. Compared to the Tesla factory this factory will have 3 times less employees but costs 15 times as much. (Tesla's investment and employee counts are underreported and outdated but I used the published numbers for estimates)
You can look at it the other way around in that you're generating $1.7 billion in taxable property value and only having to serve 2,000 jobs worth of costs. $1.7 billion in taxable value is worth ~$7.8 million a year in taxes for Williamson County.
That being said, there really are not as many knock off effects of a chip fabrication plant vs a car manufacturing plant. Cars are big bulky part filled machines that take a lot of outside coordination to get from raw material to a delivered product. Chips will largely start and end within the Samsung facility so there will be little associated facilities to tax to make up for short taxing the Samsung facility.
These are also not places you want to live near. The processes used to manipulate atoms into wafers of billions of transistors include some of the nastiest chemicals you can imagine as well as massive power requirements. If you look at the existing Samsung plant in Austin you'll notice that even though it's relatively well located there isn't really that much development around it. That's changing now with high price of land but the Samsung Plant combined with the large landfill a couple miles away created a dead zone of development in that part of town.
As far as the effects of what gets built around the new plant sprawl is going to sprawl. There's really not much else you can do in that area. No one is going that far north and asking where they can find nice townhouse in a walkable neighborhood. Hutto will be the most affected and Round Rock will get a lot of the demand as well. My guess would be that Taylor continues to see the least amount of development. All things equal developers were already building at full capacity. Austin metro is extremely labor constrained right now so this doesn't really affect much. Everyone will continue to build as much as possible.
Interesting links if you want to look at the infrastructure plans for the area. The county can barely keep up with road planning and construction before development leapfrogs it and gets in the way of the little planning that is able to be done.
Williamson County Long Range Road Plan
https://www.wilco.org/language/es-mx...portation-Plan
Hutto Thoroughfare Plan
https://www.huttotx.gov/DocumentCent...lan-PDF?bidId=