Always look at the QVL (qualified vendor list) on the motherboard manufacturer support page for the particular motherboard, especially with AMD CPUs on B450 boards.
I'm sure that there is 3200MHz memory that will run well, just choose wisely to avoid issues. The Picasso CPUs are a little harder to find data on than the others though, you may be wise to select a memory and then contact the memory support techs for assurance.
So I eventually found quite a few posts saying 3200mhz RAM will work just fine, stating that 2933mhz is the memory speed AMD supports best, paraphrasing, but should still work with 3200Mhz, and decided to buy the following combo:
Ryzen 3200G CPU
GIGABYTE B450M DS3H
G.SKILL Ripjaws V Series 1x16GB Model 3200C16S-16GVK