The man is a machine. I read an interview where he described his process, with detailed outlines and co-writers. Understanding that made the publication schedule make more sense. He's less a traditional novelist and more a showrunner for a TV series of books. The 'order' is just the airdate schedule for different shows in his network.
I tried to make a list once and got hung up on the 'BookShots'. Those are the short, cheap thrillers he did for a while. Do they count as full books? They have ISBNs. What about the 'Murder, Interrupted' true crime stuff? I decided yes, because they're sold as books. But it shows how you have to set your own parameters before you start.
I appreciate the completists out there. There's a satisfaction in mapping it all out. For them, I'd suggest using a site like Goodreads. You can filter an author's books by publication date and then manually sort them into series. It's a project, but it'll give you the master list you crave. For casual readers, this is all way overkill.
I think the best experience is release order within each series, but mixing series is fine. You'll get a sense of his pacing and how his style changes with different co-authors over the years. It's like watching a director's filmography.
A pragmatic tip: focus on the series you care about first. If you love detective thrillers, do Alex Cross and Women's Murder Club in their own publication orders. Then, if you're still hungry, slot the standalones and other series into the timeline based on your list.
Trying to read every single book he's put his name on in strict order is a multi-year commitment. The man is a publishing machine. Be strategic, or you might burn out before you hit the 2000s.
I'm going to go against the grain and say start with the middle. Seriously. Pick up 'Pop Goes the Weasel' (Alex Cross #9) or 'The 6th Target' (Women's Murder Club #6). If you can enjoy a Patterson book plopped into an ongoing storyline and still get hooked, you'll know his formula works for you. Then you can go back and explore the earlier books to fill in the blanks. It's a fun experiment that removes the pressure of 'starting a journey.' These books are designed to be accessible, so you rarely feel completely adrift.