[StavrosK]

Try the ESP32, it might fit the bill, although I've never worked with its Bluetooth capabilities and don't know much about them.

[wybiral]

I've experimented with those ESP32 chips from a few sources on a handful of boards (lots of cheapo knockoffs floating around) and haven't been happy with the performance or reliability of any of them for BLE. So far Nordic nRF52 holds the lead in my experience (they do cost a bit more though).

[jsjohnst]

Nordic is good, but STM32 is also affordable and quite decent.