Will the battery life will change? One article suggests it will not:
https://hypebeast.com/2021/10/apple-iphone-se-3-launching-rumor-with-xr-design
Looking ahead at the next generation of iPhone SE, the third rendition of Apple‘s budget phone is expected to release in early 2022.
According to reports, rumors suggested that the iPhone SE 3 will be dropped closer to the Spring season. Unlike its predecessor that borrows the design of the iPhone 8, the new SE iteration will adopt the exterior design of the iPhone XR from 2018, equipped with a 6.1-inch display, front notch design, 5G connectivity, and the A15 chip. The touch ID button is replaced with a side fingerprint scanner, while there will also be Face ID recognition.
Rumors suggest that the iPhone SE 3 will be priced slightly above the $400 USD price point — similar to the second generation.