Yes, the 2040 is a microcontroller.

RP 2040: https://www.seeedstudio.com/XIAO-RP2040-v1-0-p-5026.html

RP 2350: https://www.seeedstudio.com/Seeed-XIAO-RP2350-p-5944.html

Nordic Semi nRF52840, Bluetooth only board: https://www.seeedstudio.com/Seeed-XIAO-BLE-nRF52840-p-5201.html

There are a few others by this manufacturer of different chips, none quite as fast as the ESPs though:

https://wiki.seeedstudio.com/SeeedStudio_XIAO_Series_Introduction/

I'm only linking the Seeed ones because they're high quality. They're also the only ones I've found this size with built in battery chargers.

Hope that helps. Oh and as a bonus, here's someone using the RP2040 and an OLED to turn a lego brick into a Doom machine:

https://youtu.be/TJHSMpYi8bg https://youtu.be/6wBrOV2FJM8