So this waveform looks fine - PWM at 50% duty cycle and 10kHz frequency, which is the frequency you chose.
You’ll have to zoom out a bit on the oscilloscope and then you should see that PWM duty cycle varies over time.
And if you show more than one phase at the same time you should see that there is a difference between the phase signals if you zoom out so that you can many PWM periods at the same time.
Please zoom out more and display more than one phase at the same time. You’ll see that the waveforms are not actually the same, even though all the phases carry a PWM signal that looks similar when they are viewed individually…
I don’t know where you got the IR2104 drivers, but I came across drivers that worked only when I connected the PWM output of the microcontroller to the Input and SD pins at the same time. I.e. I used esp32 and outputs 25, 26, 27 in 3 pwm mode. I connected 25 pins to the input and sd pins of the first halfbridge driver, 26 pins to the second driver, and 27 to the third.
Looking at your vertical video I would say you still have clipping in this signal. Given your motor is 0.6Ω, perhaps you should set the motor.voltage_limit to something low, like 1V, and see if this helps things. You’ll have to watch the currents on a lower resistance motor, especially in open loop mode.