Hi @martijn,
Question the esp32-C3 supermini has bluetooth onboard i think ?
Probably yes, type BLE (I'm not sure about the "classic" BT). To use the BLE on Ai2 side you shall use the extension written by E.W.Patton
Though the BLE BT is more complicated than the classic BT, the advantage is that it isn't a point-to-point, so you can connect more boards to one app.
You can find a lot of topics on the matter (BLE) by searching the community.
Best wishes.
PS, if you continue to experiment with the HC05, please be aware that it is only a classic BT shield.