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.