Three Italian league teams were considered as finalists in three separate tournaments where two teams were already considered as runners-up but Fiorentina and Roma were the runners-up but they dominated the match but luck was not on their side as they did well in the finals of two separate tournaments and eventually don't won the trophy. Now as the last team of the Italian League, Inter Milan will play the final of the UEFA Champions League where their opponent is Manchester City.
Manchester City is a tough opponent for Inter Milan in this tournament as well. As you said win against manchester city is impossible without a good counter attack i also think the same as inter milan will play defensively so if they can score it on the counter then they can win against city.
The fact that three teams from Italy reached the finals on three different European competition is good enough success if you ask me. They may end up losing all three, but no other league has ever produced something like that.
The closest one is premier league with 2, UCL and Conference league, and then just Sevilla from la liga as well. That doesn't mean that Italy is the best league or anything but certainly something that puts them ahead of some other leagues, I would put them to third place EASILY, because ligue 1 and Bundesliga didn't produced anything like this. So, it is easy to say it is La Liga and Premier league at the top two, ranking is difficult of course, and I think it is quite easy to say Serie A definitely comes right behind them.