I think you are forgetting that they bought 3 defenders in the summer. Rudiger, Gyomber, Digne... And got Castan back. Their defense is just really poor. They have allowed 10 goals in 4 CL games, and that includes the game against Barca where Barca missed multiple easy chances. They've also allowed the most goals of any top 5 team in Serie A at the moment.
Anyways. They play attacking football and score a lot against mediocre teams, but they will get destroyed by the better teams in the competition. They won't outscore teams like Barca, Madrid, PSG, Bayern, ManCity... Those teams all have far more offensive firepower than Roma, and have far better defensive records. Roma hasn't beaten anyone good this year. Not in Serie A, not in Europe. They'll be found out in the Rof16 assuming they actually beat BATE this time, which isn't a given.
And us, we'll sneak into the Rof16 in 2nd in the group and get smashed.