How safe is Raspberry Pi? Everybody seems to be using that now. Classic Arduino is too cramped.

(I always wanted something in the middle. Some QNX-like OS in ROM, but will run without a file system. About 1-2MB of RAM.

Raspberry Pi was never really that open hardware-wise. They've IPO'd and gone fully corporate/profit driven now.

The ESP32 is probably the most vibrant platform now.