1600 and AB350M are not design for OC, I assume you already tried manual adjustment by increasing voltage related setting and increase speed.
I'd start with make case cooler (faster case fan), use fast NVMe you can afford, and upgrade CPU cooler. Pushing power related component (VRM, Chokes, mosfet ) to its limit will degrade those parts faster and may kill one of them (one dead part = whole motherboard is dead).
You can start by maxing up any voltage setting available on BIOS setting and then speed related, test your setting with stressing tool, you'll know eventually at what configuration your system can go.