Please consider our app - Jitbit Helpdesk? Disclaimer: I'm one of the developers so I'm not posting any reviews/pros/cons since I'm obviously biased.
We have both SaaS and self-hosted versions and the SaaS is $69 for 4 agents ($17 per agent). All the features you mentioned are there.
I would have to agree with Markus in saying that project/task management tools would be the best choice in this case. Depending on what the other teams are already using, you could do one of two:
Add in new tasks into their existing boards and tag them as Feedback
Create a separate board for feedback and add in the tasks there, separating them with ...
Have you considered Jitbit Helpdesk Ticketing system? Disclaimer: I'm one of the developers so I'm not posting any reviews/pros/cons since I'm obviously biased.
But since you mentioned you need a self-hosted app for a Windows server it seems like a perfect fit. It's basically the only self-hosted helpdesk app for MS stack (.NET based)