I’ve always followed Ellis’ guide start to finish. It really makes a huge difference in print quality and especially consistency of printer performance.
As for filament, I’ve found brands I really like that have good and consistent quality and stick to those. Before when I was trying different brands, I found I had to tune filament settings every time I tried a different brand which got really annoying.
I would definitely still tune extrusion rate on the printer profile and flow rates and PA for each filament profile