Arsenal's team was more stable and stronger than Juventus's. However, they lost against Sporting's match tactics. I wouldn't say that Sporting performed too well against Arsenal. Arsenal performed well in both matches but failed to qualify for the next round. There is no reason to think that Juventus will easily win against Sporting. The first leg is Juventus' home match. If Juventus don't win at home, I don't think they will qualify for the semi-finals. Juventus must win the first leg.
You are wrong. Arsenal's defeat to Sporting in the second leg, purely because the Gunners' secondary players did not have the same quality as the main players. you can see, when Arsenal didn't play Odegaard, Saka, Partey. plus, two of Arsenal's core defenders, were pulled out due to injuries. so, I will say, if from the start Arteta played his team's full starting line-up, it would not be a difficult problem for the Gunners to overthrow Sporting. however, unfortunately, Arteta preferred to play Fabio Vieira and Reis Nelson. Because, Arteta prioritizes the Premier League.
but anyway, I have to admit that Sporting Lisbon did quite well, in fact they really worked hard in that game.
For Juventus, however, this club from Serie A should not be underestimated. Juventus is one of the strongest challengers in this competition apart from The Red Devils. I am quite optimistic that Juventus will show their best game when they host Sporting later. so let's wait, and see in the game later.