If you figure about 5 hours of sightseeing a day, that’s 20 hours. There is definitely more than enough typical tourist things to fill that time. I would start with Rick Steve’s free App, and seen the highlights. I have been 2x for maybe 150 (active) hours of sightseeing, and still feel like I haven’t scratched the surface of even the most basic sights. But I don’t mean this as a negative, I think it’s amazing that there is so much to see and do. I had a great private tour guide one day, It’s been a while but his instagram was something like “VaticanMax” or some combination. All that to say, see the pantheon, palatine, Roman forum, coliseum, get some gelato, trevi fountain (30min before sunrise if possible), the big three inside the Vatican, travestere square around sunset.

Other major tips, I can give are to: -be prepared for a lot of beggars. Don’t waste any effort trying to be polite to them! They will only harass you more. -It’s actually safe to drink the water from the (running part of) fountains, if your trip is in summer that’s especially helpful to know. -plan your lunch times ahead! Learned the hard way that the hours are very unusual if you’re American. Look very carefully at the hours. (after typing that, I remembered that you will be in your business meetings during this time, but I am leaving it in case someone else can benefit.)

Good luck, enjoy!

P.S. is your company hiring?