You alluded to this already but ESP32 et al is really awesome but they (and arduino) are microcontrollers, not mini pcs like a raspi which have very different purposes.

You CAN run a webserver on a microcontroller but you’re essentially writing a program to do so. On a raspi you’re installing a full OS and then installing apps (nginx, Apache, jellyfin etc).

Conversely raspi has GPIO which can be used to easily interface with electronics just like the ESP32 but now you’re stuck maintaining a whole os to make your LED blink.