Distances look small on a map, but crowds, security checks, and pedestrian surfaces change the pace of a day in Rome.
Build days around areas
The historic center, archaeological area, and Vatican work better as separate days or half-days.
Leave space between reservations
Do not schedule two timed entries without enough time for travel and security checks.
Practical note
Information about tickets, schedules, transport, and access can change. Check official sources close to your travel date.