Optiplex 3050 M2. Slot for SSD or only for wifi card?

Hi!
I have an Optiplex 3050 Small Form Factor.
Can I install an M2 PCIe SSD in this computer?

Currently there is a SATA SSD and an optical drive installed.
The computer has only two SATA ports (very stupid), two 2.5 "slots but also optical drive. (Three possible SATA-drives by only two SATA Ports)

I would like to install a 1TB SATA hard drive, keep the optical drive and still have an SSD as a system drive.

I have seen that an M2 slot would be present in the PC. The manual, however, states that this is for a wifi card.

Is there really only one Wifi card? Or can I use the M2 slot for an SSD?

Many Thanks
Max