Yeah, portables have to be vented out a window adapter, otherwise all the hot air stays in the room.
With a 6" hose, you need 28-sq. in. of inlet from a window.
If you have a window that's 24" across, you only need to open it, say 1.25" to have a perfect opening.
Make a cardboard box of the same size as the small window opening, making sure that sticks out just far enough from the window frame so that you can connect a 6" hose to a hole cut into the top or bottom surface (or even a 4" or 5" hose & hole), and then run that duct to one of the tent's inlets.
A small & thin ducted window insert will hardly be noticeable compared to a window insert with a 6" circular opening in it.
Paint it black on the inside, and it's pretty stealth.
If the tent's inlets are blocked/closed, cool air will be drawn in from the window through the auxiliary duct, without totally freezing you out in the room.
This would allow you time to save for a portable A/C unit for when summer arrives.