Possible to use the RPI as a WiFi extender/repeater?

As title shows
I’m running a RPI 3 in my living room (running OSMC ofc) it’s connected to my network with WiFi, is it possible to use it as a WiFi extender/repeater as well? I mean its just sitting there anyway,

I see that I can goto “My OSMC>Network>Tethering” but I only get the options:
Ethernet to WIFI
WiFi to Ethernet
But not WiFi to WiFi?

Is this possible?

WiFi to WiFi is not possible.

Oh dammit, what if I use a extra WiFi dongle? Then it would be possible right?

In theory, but haven’t tested this, and I’m not convinced it will boost the signal.