It's hit or miss.
With the original Ryzen CPUs, a person was wise to buy memory known to work properly.
The Ryzen refresh (2700X, etc.), memory compatibility was improved quite a bit, but not every module out would work at stated speeds (or not at all in some rare cases). I think people wanting to populate all four DIMM slots were the ones that had to be the most careful with what they selected.
RAM prices have been falling over the last several months, so honestly I would just wait and see what works best with the motherboard you pick out. Motherboard manufacturers don't seem to have their RAM QVL lists published yet for their X570 motherboards. However, if you're pre-ordering the new Ryzen stuff, you will just have to roll the dice on a set and hope for the best (I imagine modules that worked well with B450 / X470 motherboards would be a safer choice).