I think Atalanta is far better in all aspects compared to the Milan atm. I do like how man on man's marking strategy by Gasperini. It's always doing very well in the big match, and i expect him to do that again soon. They get 2.06 for a home game, that's very tempting odds, but the gap to ward Milan is not that big.
To bet on 1x2 Atalanta which is very dencent consider we can double our money. 2.5 goals are even offered less than 1x2 Atalanta, but as you said, it's likely to happen. I personally wanna choose a direct bet to Atalanta instead of consider other options.
The concern in this case is how Milan will try to take advantage so that the conditions remain a point in every match they do.
Atalanta with Milan at the moment when talking about the actual game scheme is very good and Atalant is better than Milan who are monotonous and sometimes they prefer to secure 1 point by playing passively rather than trying harder to keep and change the score in a match.
Atalanta is one of the clubs that I categorize as a club that will be troublesome for the opponents they face so in this case there is a hope that Atalanta can show a very good game in conditions of doubt about Milan's appearance which is sometimes always monotonous in every match they do in Serie A.