I have made a promise to myself to stay away from any match that has Atletico in it in the remainder of the league. They are very unpredictable and lose when you don't expect them to.
That being said, another reason why I would be avoiding this game is that Osasuna will be playing at home. Playing at El Sader is difficult for almost everybody. They make it difficult for their opponents, especially the big teams. Barcelona and Real Madrid have both dropped points there this season.
Theres also the fact that Osasuna are chasing a spot in Europe while Atleti donr have much to fight for so Osasuna might be more motivated. I honestly do not know how this game will go so I wont be betting in it.
You are right that Osasuna is a big team and a tough opponent at home. It is very difficult for Atletico Madrid to win at this ground. Although Atletico Madrid is in a good position and their recent form is also quite good. But how terrible Osasuna is at home can be understood by looking at the statistics of this ground.
I agree with you that it is better not to bet on Atletico Madrid in their matches. Because, since the beginning of the season, I have seen that Atletico Madrid has been performing unexpectedly. It is also very difficult to predict their matches. Especially in the match against Osasuna, I will not agree to bet on Atletico, although I will support them.