Does the Samson Q2U already record over its own USB connection?
Yes. The Q2U already contains its own converter and plugs straight into the computer over USB. There is no separate microphone preamp in this chain.
Use the Samson Q2U on its own USB cable. The recording path is already inside the microphone, so an interface is a second device, not a missing piece.
Do not also run an XLR lead into an interface unless you mean to record that way instead. Two connections at once are two clocks. Set the mic's own level so a normal voice sits with a little space before clipping, and keep it close enough that you are not compensating with software gain.
Treat the knob on the microphone as the gain control. A hand's width from the grille is plenty for speech. Leave the DAW fader near unity. If the take is quiet, move closer before you reach for a software boost: that boost cannot invent detail the converter never saw.