Global entry conditional approval (CA) is very random. Mine took 4 days. DH took 6 months! Both applied at the exact same time.
Finding an interview slot depends on location and possibly timing. I found mine within a month of CA. Friends of mine who applied a few months before me, found their interview slot almost immediately. DH originally could not find any openings within a day’s drive for many months, but spots open randomly. After checking the website daily, he was finally able to secure one a few weeks in advance (but it was also a 5 hour drive from our location).