So I'm thinking of buying 32gb sticks of corsiar vengeance rgb pro at speeds of 3200mhz cl16 and my motherboard is a gigabyte a520m s2h so I'm really curious if the ram will work at stock/rated speeds without needing to overclock and also not to waste time and money.
You need to look at your Gigabyte Motherboard Specs for RAM Memory to answer your question.
The motherboard is the one that determines who much RAM you can install in total and per DIMM Slot and at what speed it can run at.
According to the above specs your motherboard supports a total of 64GB of RAM with a maximum of 32GB Ram Module per DIMM slot.
It shows that you can Overclock your RAM if you want it to run at its Native speed and not at its SPD speed. Above shows the various Ram Speeds your Motherboard supports.
Without Overclocking you can run RAM Speed at SPD of 3200Mhz. That is if your RAM SPD is 3200Mhz.
If you look at the Motherboard's RAM MEMORY QVL LIST for you Ram Memory part number it will show the maximum speed supported, how many DIMM Slots you can populate and support, How many GB per RAM Module it shows it will support, plus whether you can Overclock the RAM or not.
Here is Gigabytes QVL List for the Renoir APU (4650g APU): https://www.gigabyte.com/Motherboard/A520M-S2H-rev-1x/support#support-doc