We use the STM32F446 for a new project. We noticed that the clock for the timers on the APB1 is x4 instead of x2 when the APB1 prescaler is not equal to 1.
In our test we have used a system clock of 168MHZ and APB1 prescaler /4 which gives 42MHz. Cube says that the APB1 timer clock is 84MHz but my output signals on the timers are twice as fast. We have checked the 42MHz on the other APB1 peripherals with UART5, there the timing is correct.
Please udate the reference manual and the Cube for this device.
And maybe also indicate that the USB peripheral for this device is like the F7 USB core...