I am using CircuitPython.
The XIAO product page says: A1/D1 to A10/D10 Pins have PWM functions
If pin set to D6:
pinPWM = pwmio.PWMOut(board.D6, frequency=5000, duty_cycle=0)
→ REPL reports "ValueError: All timers for this pin are in use"
pinPWM = pwmio.PWMOut(board.D4, frequency=5000, duty_cycle=0)
Is it possible for someone to hook up D6 to PWM in Micropython?
You probably need to check with the circuitpython project. The core python can control the use and allocation of timers and pins. I don’t know what that the particular conflict is, but D6 on the XIAO can also used for the UART TX (D7 is associated with UART RX), and is aligned with SERCOM4 (a SAMD21 serial controller) and TC4 (a SAMD21 timer). There may be an initialization process in circuitpyhon that consumes some of those resources.