They are using the Next Gen cars now. Here's an article listing the differences between last season's cars and the Next Gen cars:
https://www.cbssports.com/nascar/news/nascar-next-gen-car-explaining-the-ins-and-outs-of-the-nascar-cup-series-new-racecar-for-2022/
Some of the changes are a shorter greenhouse, shortened deck lid, and widened track width, as well as 18" forged aluminum wheels and wider tires. The wheels will feature a single lug-nut design, as opposed to the traditional five lug-nut design of previous generations. Interestingly, the Next Gen cars "feature upgraded specs to match modern passenger vehicle technology, including an independent rear suspension, rack and pinion steering, and larger brakes." Does this mean that they are becoming more like "stock" cars?