Ostia Antica from the Rome airport

Hi, I’m wondering if anyone has tips on visiting Ostia Antica from the Rome airport? I searched the Forum and there hasn’t been a discussion of this for several years. My friend and I have a day to kill at an airport hotel and we’re wondering what to do around there besides getting our COVID tests. I know we can take the train into Rome from the airport but we will have just spent a week in Rome. Not that you can spend too many days in Rome, haha! But just wondering about Ostia Antica, since it seems kind of close to the airport. We won’t have a car.