WikipediaThe Capuchin Crypt is a small space comprising several tiny chapels located beneath the church of Santa Maria della Concezione dei Cappuccini on the Via Veneto near Piazza Barberini in Rome, Italy. It contains the skeletal remains of 3,700 bodies believed to be Capuchin friars buried by their order....
https://en.wikipedia.org/wiki/Capuchin_Crypt
When we visited in the early 90's, this place was completely under the radar, but it doesn't seem so much anymore due to social media, etc.. You don't need a lot of time there, so you can squeeze it in between longer lines and tours.
In answer to your question - yes, there is plenty to do and see for five days in Rome.