We will be flying in to Rome for only two nights before leaving to Sorrento for a wedding. Would like to be able to walk to the many sights.
You might consider going on Booking.com and looking for properties in the Pantheon area. It's centrally located for walking, and buses are two or three blocks away. Restaurants are also good in the area.
We stayed in an Air BnB in the Piazza Navona/Pantheon area in 2018. Vatican is a (long) 20 minute walk but most other major sites are a pretty easy walk (Trevi Fountain, Spanish Steps, ect)
For only two nights, I’d probably use a taxi if you need to get somewhere that isn’t walkable if you aren’t near a metro line. (As in please don’t walk to the Colosseum and Forum). We got really familiar with the bus system as it’s easy to use once you get the hang of the web site, but I wouldn’t bother with it for the short time you have.