(I’m not author of this)
I just saw this interesting blog / article:
When you’re cranking, every second counts—the minute or so it takes Linux to boot up feels like an eternity. DietPi is a minimalistic, stripped-down Debian-based image that prioritizes fast boot time over lots of immediately available default services. It shortened our startup time substantially, and turning off unneeded radio services (Bluetooth, Wi-Fi, etc.) reduced it even further: from Linux boot to a usable userspace in around 3 seconds.