the framework-arduino-samd-seeed package delivers a TimerTCC0.h you need to include. Otherwise there was some rewriting necessary I can’t remember right away. But at the end it was working.
There was something with adding a new initSAMDTimer I remember, where TimerTcc0 was initialized and attached to an ISR.
However, there is a new version of uClock available which I haven’t been able to verify.