Just looked into the specific m.2 wifi card you mentioned and there’s definitely antenna connectors on it. You’ll want to get something like an ** ipex4 to sma** cable that you will plug into the m.2 wifi card on the Main and Aux ports and then thread the screw on ends into those holes you mentioned. You’ll then need an antenna that can connect to the screw on portion. This should greatly increase your wifi performance since right now your case is acting as a shield and blocking a bunch of the signal.
It’s likely you can get the cables and antenna in one package. Your card has 2x2 mimo antenna type fyi.
Edit: something like this should work https://www.aliexpress.com/i/2251832705421976.html?gatewayAdapt=4itemAdapt
TrueNAS has a feature built in called Jails that allow you to run applications in their own walled area similar to a VM but more similar to a Container. There used to be a section (haven’t used TrueNAS in a moment) where you could easily attain official and community pre-built jails and install them without much difficulty. QBittorrent was in one of those lists. Definitely worth poking around to see if that’s still there.
Another option would be to stand up your own jail and install the program you want on there yourself. Here’s a quick rundown out there that seems to cover the basics you are looking for.
https://cyberon.org/qbittorrent-installation-in-truenas-jail.html