A professional mercenary might just be in it for the money, but everybody has their own opinion and values. Some people are more motivated by the cause, but still need to be paid.
Turkey has basically taken over the pipeline of jihadi recruits that used to go to ISIS from radical mosques and madrassas around the world. Then Erdogan uses them like his own covert foreign legion. They are mainly garrisoned in the parts of Northern Syria that Turkey occupies, but Turkey ships them abroad to fight where it suits them, telling them that it is jihad.
They sent a lot to Libya, where Turkey wants to secure a puppet government, that will grant Turkey the rights to Libyas offshore oil and gas.
Armenia was the Worlds first Christian country, and Armenians are overwhelmingly Christian. The 150,000 Aremenian Christians isolated in this disputed Province of otherwise overwhelmingly Muslim Azerbaijan, make a convenient target to keep their jihadi (mercenary) base whipped up, keep recruiting rates up.
Armenia itself borders Turkey, and there are still a lot of Armenians inside Turkey itself. Armenia is aligned with Russia, and that poses a threat to Turkey, in its confrontation with Russia. Turkey and Russia are supporting opposite sides in Syria and Libya, so this current operation is part of the chessboard in their rivalry as well.
chessboard Bump