Various ESP dev boards, Arduino, Pi Pico -- any of these are good places to get started from on the road towards doing useful things with microcontrollers, I think.

Arduino is just a familiar name with a long (~20 year!) history. There's a plethora of pre-existing projects that a person with no prior programming or electronics experience can implement easily to get their feet wet.

Some manner of ESP32 (or STM or MSP or RP2...) may be a good choice for a project for someone with some experience, but if you put a reasonably-motivated person in a room with a computer and an Arduino starter kit then they'll successfully be building simple things in no time.

It remains a friendly place to start doing stuff, and that was always the primary intent.