These days most USB-C to USB-C cables are safe. That was not always the case a few years back, where we saw USB-C cables (including one from Anker) with the potential to damage small devices. As with any electronics following the basics are a good idea. Get cables from known, trust brands and retailers. Go over reviews (on and away from Amazon). Avoid too good to be true prices.
If you really want to be safe get a USB-C cable that is USB-IF certified. Such cables should advertise that in their listings. Those cables have been tested and approved by the body that created USB-C.