Atalanta made Italy proud this season for doing what no club in Italy could do, which is winning the Europa League for the first time in the history of their club and in the history of Italy. This season will never be forgotten in Atalanta, because they were also able to win Leverkusen after 51 matches, and they are the only and first club to win Leverkusen this season.
This is a great achievement and Leverkusen that was the favorite lost out in the finals so easily without fighting back. Both teams are incredible amd I admire their performance this season.
This season Atlanta has made at least the Serie proud because as you said if Atlanta is the only Italian team to have won the European Competition trophy this season, after InterMilan failed to win the Champions League trophy, as well as Fiorentina who failed to get the Conference League this season and of course Atlanta gives little hope for Serie A to continue to show their capacity as one of the competitive leagues. Atlanta's journey in winning the Europa League this season is of course a surprise that is indeed unexpected at all, because indeed from the beginning Atlanta has never been the favorite to be able to beat Liverpool and also Leverkusen in the final.
Atalanta did win the europa league trophy this season and sorry friend if I corrected your statement a little wrongly, indeed this season europa league trophy is the first trophy won by atlanta after they last won the major trophy since 1962/63, but for serie A, of course Atlanta is not a first team that has won the europa league so far, Because as far as I know, Juventus, Intermilan and Parma have already got more than one.