Re: making things about me (but also kind of related), I am working on a project that requires sending encrypted telemetry data from a Crazyflie drone (so, STM32) and it's such a fun experience. Each telemetry payload is just 26B so I had to get creative, write down packet diagrams and then make it work in C. An AI agent helps a bit with some stuff but you're mostly on your own.

In general I highly recommend going the embedded/IoT way if you look for challenges and constraints.