Yes Osasuna is not a weak team today they are ranked 5th in the standings but when compared to Madrid, Madrid is stronger
Moreover, Madrid still holds an unbeaten record of course they will try to maintain this record therefore I agree with you Madrid will win
Regardless of how much the final score is not important the main target is 3 points.
Comparison between Real Madrid and Osasuna is a bit inappropriate in my opinion, because Real Madrid who are still unbeaten this season are only better suited to be compared to Barcelona for this season. Because Barcelona already has a very good performance and has also improved from last season so it deserves to be compared with Real Madrid which is almost the same in strength this season.
I think it's an embarrassment to compare Real Madrid with Osasuna this season regardless of the performance of Osasuna, Madrid has been undefeated so far this season in all competitions and they are currently the only team in Spanish La Liga that is topping the group in Champions League and also leaders in Laliga, the history between the two teams have been Madrid 80% win while Osasuna is 20% so there is no comparison between the two teams. Just like you said, Barcelona is the only team that can be used to compare Madrid so far but Madrid is better because they are still playing unbeaten this season.