If you need to store the dongle, you're probably best off with a male USB-C to female HDMI or DisplayPort adapter such as this Cable Matters USB-C to HDMI 2.1 Adapter.

I tried both the Cable Matters DisplayPort to Mini-DisplayPort Male to Female Adapter ($9) and the StarTech DisplayPort to Mini-DisplayPort adapter ($6.50) with the Benfei USB-C to DisplayPort 4K ...