Questions to show interest in the tech stack and system?

I have <3 Yoe as an SWE and am interviewing for a SWE role that operates at a large scale but the team I'd be joining is a very small team (2 SWEs and a manager). My interview will focus on coding and my SWE experience, but I also want to express interest in the system that I’d be working in/on.

• What kinds of questions do you all ask during the actual interview to the devs, director of IT, etc. to show interest in the tech stack and system?
• There is on-prem infrastructure, an EA with Microsoft, and data replication with a parent org-- all of which I'm not familiar with. Why would an organization choose on-prem over fully cloud-based solutions?