We are thinking of visiting Rome and the vicinity.

I am not sure that with 5 days there's anything worth sacrificing one day in Rome (not counting Ostia Antica).

We also want to go to one of the beaches near by (1hour travel or less).

I am not an expert because I don't go there often, but beaches close to Rome are not stellar, as far as I know.

And the end of August will still be high season (albeit in the ending) so expect high prices and a lot of people.

I think you should look into Anzio/Nettuno (it's about one hour) to the south as a decent option, I might look into that because we know someone that lives there.

To the north you could get to the argentario area which is nicer and more upscale but also much farther (2 hours).

You ask for the refund paperwork at time of purchase (if they haven’t proactively given it to you). Then you present that and the purse at the tax refund counter at FCO before leaving. You can choose money back to your credit card or cash. Allow extra time at airport to do this errand. ChatGPT can walk you through exact steps.

I too would not spend a Rome day on a beach.

I’m here now. Low season. But pick a restaurant near tourist area and you will see the costs double.
Espresso seen today do 5.5 euro in Piazza Navona (massive tourist trap). Everything here is overpriced in the city. But in some areas the prices seem reasonable. There’s a large suburb called Trastevere. It is small streets filled with small bars and Ostria. Seems to be a fun place where locals also eat. Food is reasonably priced. Also found a great place with 12EU a litre for table red wine that was actually really nice. We started at Carlo Mento Ostria for dinner (link below) then walked the streets surrounding it. But there’s heaps of places to eat. Some highly expensive. This one did a nice sausage and mushroom pasta for EU12. Pizza etc.

https://maps.app.goo.gl/si8NpSbYPSdTXbJV9?g_st=ic

For 5 days I'd stay in Rome, maybe last day for Ostia beach (not the best beach)/ Ostia Antica. Stay at the same place: Piazza Navona, Fontana di Trevi, Spanish Steps, Piazza del popolo. Less €: Termini (I stayed there) or Trastevere

For 4 days in Rome:

. 1 day Golf Cart with Local Guide or a foot tour to get a taste of the city + fountains and squares + Pantheon, Piazza Navona, and Monument to Vittorio Emannuelle II. Finish the day at Capitolin Hill (nearby Capitolin Museums)
For Pantheon get there an entrance with money, it's pretty fast or on a tour. You can go to basilica di Sta Maria Magiori, near Termini, on this day

. 1 day to a Colosseum+Forum+palatin on a tour: option 1, option 2, option 3 but you can also just buy the ticket on oficial website: https://ticketing.colosseo.it/es (be aware of different ones) + Campo di Fiori and Trastevere in afternoon, sunset in Gianicollo Hill

. 1 day to Vatican Museums + St. Peters Basilic. Tour with the official website: https://ticketing.colosseo.it/es St Peters Basilic entrance is free but if you want to go to the dome or with a tour book in advance. Or go for a Vatican Museums, Sistine Chapel and St. Peter's Guided Tour. You also have St Angelo castle, visit it or just go around it

. 1 day other places: Monument to Vittorio Emannuelle II, Torre di argentina, capitolin museums, Borghese Gallery, Palazzo, Scala Santa, Boca della veritá, Arancini Gardens, Hole to Vatican, maybe even Basilics St Giovanni in Laterano, St Paul fuera de mure or Termes di caracalla. Or even further: Tivoli or Pompei + Amalfi Coast

Go for pasta workshop or to Ostia Antica/ beach last day. Enter every church. Rome is a city to walk but transports are only 1,50€ up to 100min

From Fiumicino airport: Leonardo Express (14€) or shuttle for 7€ in advance, for example here or 9€ on spot. Also taxi for 55€ (aurelian walls) or private transfer