Hi there,
So, "fortnite" is an archaic word that we don't really use anymore in modern speech, although it does mean two weeks. In this circumstance, a more natural way to say it would be to use "I get paid" along with "biweekly," "every two weeks," or "every other week."
"I just got a new job, and I like it because I get paid biweekly."
"I just got a new job, and I like it because I get paid every two weeks."
"I just got a new job, and I like it because I get paid every other week."