I'll be brief : when trying to execute the Ascension.exe and it starts to extract the files in the game's directory (GOG) , it just interrupts with a message error which (actually you only "hear the sound " and do not see the error display , which i believe is the kind of "not enough resources..." one , as if there is a memory leak for the process to complete or something but i am not quite sure , again , the message error is quick to disappear) prevents the "setup.exe" to be extracted in game folder...i think( i say this because , when running SCS.exe it successfully extracted the files , included the "setup.exe" one , and got ready to be installed) ; also the game is unmodded , i wanted to install Ascension first.
EDIT
i just tried to scan the "Ascension.setup.exe" and it was labeled as "infected" by MacAfee ; also is this setup.exe file which cause problems with the installation.
EDIT
problem solved , i just had to use a more updated version of weidu ( https://github.com/WeiDUorg/weidu/releases/tag/v247.00), copy the weidu.exe file in game folder
and rename it "setup-ascension.exe" (not my idea ) ; so whoever has other problems , maybe can find this helpful.