You cannot directly download an older kernel. But you can use the ( catalog.update.microsoft.com ) to search for a specific KB update that includes that kernel version. Then manually install that update package.
: It does not receive official support from Microsoft, and features like Windows Update or standard telemetry may be disabled or modified.
The kernel is the "brain" of your operating system. It is the first program that loads after the bootloader and acts as the bridge between your hardware (CPU, RAM, Disk) and your software (Chrome, Office, Games).