Hello @oyyodams.
Long time ago since this issue game up.
Yesterday I updated recalbox to 18.x then I tested again to connect. it did not work but:
Since Recalbox 4.0 I always used a HAMA Bluetooth USB adapter because 4.0 did not support bluethooth chip from raspberry pi 3.
Anyway: this time I plugged out the HAMA adapter and I could use the internal Bluetooth connection of the Raspberry Pi 3.
IT WORKED
So I think Bluetooth worked without USB Adapter since 4.1?
Anyway: this issue is resolved

thank you.

I have the same problem.
This does not work:
"Turn the Nes30 Pro on, then push the PAIR button for more than 3 seconds to delete the previous pairing information. Then in Emulation Station, add a new controller."

I reinstalled version 4.0.1 -> works
I make fresh install of 4.1 -> does not work
I upgrade from 4.0.1 to 4.1 -> does not work

seems like a bug in 4.1

Nes30pro controller tested with FW 1.7 and 4.0
No difference.

br chris