ESP32 - quite a range of dev boards and places like Seeed and Adafruit have a nice selection of accessories. Adafruit develops CircuitPython which is IMO the lowest barrier to entry for programming MCUs. Adafruit even has CircuitPython sketches on their site for how to interface with the components they sell.
Rust on ESP32 is still a bit early - the HAL crate is still pretty unstable, but the toolchain is quite nice and I'm able to be productive enough that I never reach for C or C++.
Rust on ESP32 is still a bit early - the HAL crate is still pretty unstable, but the toolchain is quite nice and I'm able to be productive enough that I never reach for C or C++.