I did a few more steps, now it seems to work the DLCs:
-in a steam discussion about the same issue, an Ubisoft personnel said:
" 3. As a final workaround, can you please try installing another build of the game >
In your Steam library > right-click on the game > select Properties > select Beta tab > in the beta access code type > JustInCaseWeNeedIt > Check code"
-then I opened the game and did the following steps: [space button] > options > Restore default options > restart the game
Thank you for all the support, I hope his helps other people as well