I've had a day or two to use Rosegarden running under Raspbian to make practice loops on a Pi4B 8G, ondemand overclock to 2000 MHz, USB HDD root filesystem.
Perhaps I'm not that exacting about precise tempo settings, but I didn't experience anything I would call off or wrong. The beats I hear sound accurately placed, so I'm very happy with Rosegarden running under Raspbian buster with it's standard kernel.
My internet readings claimed a timer frequency of 100 Hz from one source and another claimed 250 Hz. I have no clue which is correct, but the timer's low frequency is said to be the cause of the low resolution.