Add more PCIe slots to your mining motherboard - YouTube
If you need more PCIe slots, you will need to replace your motherboard with one that has more slots.
2 RAM Slots Motherboard | Pangoly
The M.2 and x16 PCIe slots on a motherboard house the Ryzen 5 3600 must run PCIe 4.0. With this card, a reasonable amount of RAM clock speed overclocking should be possible.
Best B550 motherboards in 2024 - XDA
Despite its price tag, this B550 motherboard has all the necessities: four DDR4 RAM slots, two NVME slots, a couple of PCIe x16 slots with Gen 4 connectivity, support for ARGB, and more.