I usually just pick one that works. It depends on how realism you want it to be. For me, I’m not a casual simmer, nor am I a serious one. I’m just somewhere in between.
I don’t use Fenix, but with the FBW A32NX, I just followed the most common checklist, but also skipped a few things because I don’t need to check them (since I have failures turned off anyway). Things like APU and Engine fire test and stuff. While they are important step to do in real life. It’s just a waste of valuable time for me seeing as I will never experience an APU or Engine fire anyway.
So I follow the proper procedure as a foundation, and as I understand the steps a lot more and how the aircraft behaves, I start optimising my own checklist to have the minimum steps I need to do to get myself up in the air as quickly as possible. I know it’s unorthodox, and definitely not a good habit to get into. But hey, I’m not a pilot in real life and I probably never will be. So I’m pretty free to have a bad habit or two. But different people might see it differently, and that’s okay.
And then, I also use a tool called FS2Crew, which runs as if I have a copilot with me, and she helped me with going through the proper checklist anyway, and allow us to split the workload, leaving me with more authority to handle my own flow as pilot flying, and the copilot doing the pilot monitoring responsibility.
So to answer your question, follow whichever one you feel is best for you.