In short, from the underlying principle, there is no essential difference between 28nm and 5nm chips, but different scenarios have different requirements for chips, and those who pursue stronger performance, or products with size and energy consumption limits tend to pursue more advanced processes, but this approach tends to cost more.
Those scenarios that are not so high in performance requirements and are not sensitive to size energy consumption tend to use older processes, after all, this is more cost-effective.
The 5nm chip process integrates more transistors per unit area than the 28nm chip, saves more power, and generates less heat
The application field is different, the accuracy is not so tangled. It's just a matter of size. In short, I have a 5nm process. Can produce something five times smaller than you at 28 nanometers. It's not like a few nanometers will stop our plane rockets from flying. We're missing the chip design.