20t6

I have 8 GB 3200 Mhz ddr4 ram soldered in my ThinkPad gen 2 AMD Ryzen 5 laptop. Machine info: Thinkpad E14 20T6 I checked in CPU-Z and it shows channel # 1x 64-bit. Can someone tell me if should I buy 8 GB single channel or 16 GB single channel or 16 GB dual channel? I have one empty slot and...