You are correct, since Inter Milan did not compete in any other league but Serie A, they may not take any of their opponents lightly. Despite the fact that Inter Milan now leads the Seria A table by 14 points, they will not lose any of their games simply because they are at the top of the league. This is the greatest choice for Inter Milan; they need to lose one and focus on one. They have been eliminated from the Champions League; now it is time to make a record in the Seria A league to give their competitors a major numbers advantage. Inter Milan may use their anger at being eliminated from the Champions League against any of their opponents because it is the only trophy they have to win this season.
When Intermilan were still playing in the Champions League of course they were also in a leading condition in Serie A, so I think they never underestimated their opponents so far and even we can see when they were also focused on two different competitions, inzaghi stay to played the their main squad, currently intermilan leading with a difference of 14 points with only a few games left, of course Intermilan is required to continue to perform consistently until They are celebrating the Scudetto Championship this season.
At the moment I think, Inzaghi just needs to wait a few more games for them to celebrate the Scudetto, and after they do the celebration then maybe Inzaghi will try to do an experiment by prioritizing their reserve players to fill the line-up to spend the remaing of the game, if now they do the experiment of course it will be very risky and certainly it will interfere with their chances of winning the Scudetto sooner that they planned Later, for now my prediction, Intermilan will be able to celebrate the Scudetto when the Milan derby match is played and on the condition that InterMilan can win the derby match.
I don't think Inzaghi needs to experiment with making some changes to his line-up in the remaining matches. Even though Inter is currently far ahead of its competitors, I think they should not lower their tempo, if Inzaghi always maintains his main squad then it would be better to secure the Scudetto more quickly. I'm pretty sure the Nerazzurri will celebrate the scudetto this season and that would be a great achievement for Inzaghi's career. Of course it would be very beautiful if Inter were able to celebrate during the match against AC Milan, it would be something very perfect for Inter and its fans.