Yes, there is only one timer that supports inverted channels. But this is not just the case for Bluepill but for most of the stm boards.
That’s why there is the software configured one.
The benefit is that you can drive more motors.
The problems are:
- you need at least two timers for one motors
- the timers are not perfectly synchronized (not too far, but not 100%, the timers are started at the same time)
- this will not cause any problems in terms of foc because the low/high pairs are in perfect sync
- the problem can come in current sensing when you need very high degree of sync with the adc
So in your case, there isn’t too many drawbacks in terms of performance.