Milan no longer has to target for a win or a draw in the UCL match because it will only endanger players for injury. There is nothing else that should be prioritized for Milan other than Serie A, because this season Milan is very likely to get the Serie A title. Considering the current title contenders are both in an unstable condition and maybe only Napoli will be the toughest competitor when this, but even so I still have high hopes for Milan even though I'm not a fan of them.
Milan are realistic in Champions League because they see a very minor chance to go next. Moreover, even if they go next, they will not have too good chance to win next rounds.
Rather than wasting their resource for Champions League with vague hope, they should concentrate resource for Serie A where they are in the top standings and are fighting with Napoli, Inter Milan for Scudetto. Win the Scudetto this season and return stronger in Champions League next year. It's a good plan.