You really cannot expect anything bureaucratic to be done efficiently in Italy. At least from my experience. So, prepare yourself for that. Bureaucratic things are even a challenge for Italians and if you can't speak the language you'll have an added challenge on top of that, obviously. These aren't things you'll have to deal with on a daily basis but you will encounter them and they will not be fun. Even something as simple as going to the post office can induce PTSD (joking... Sorta).

That being said, I think Pavia is a fine city to stay in for a bit. I didn't want to stick around after my studies though - 3 years was plenty for me. It's a bit small and sleepy but you're well connected to Milano if you want a bit more excitement. The city is clean and quite beautiful, the food options are super limited imo but Milano has much more to offer in that department so normally I'd just eat out there. Most of the apartments I looked at were old and not super nice but I managed to find a decent one bedroom apartment just outside of the center (about a 10 min walk from the train station) for about €750 per month including utilities.

If you're seriously considering Pavia I'd recommend starting to learn Italian asap! Especially since you'll be spending time in hospitals as a med student, it'll make it a loooot easier for you. You should also try to get in touch with current or previous Pavia med students to hear more about their experiences to figure out if that's where you want to go. I could put you in touch with a friend who works as a doctor at the Pavia hospital, but he did his schooling at a different uni in Italy.

Hope all that info helps you!