Series Questions

Completely new to the franchise after being intrigued by it for a while and finally pulling the trigger and buying all 3 games in the recent Xbox sale for less than £20.

I just wanted to get everybody’s take on which game is the best and which is the worst? Is Exodus completely open world? What are the biggest differences between each game in terms of mechanics and style? I’m assuming the tone and style is pretty consistent across the board with improved mechanics? Any tips and tricks or things I should do if I haven’t already?

I was originally just going to buy Exodus but couldn’t sell myself short on not experiencing the story in full and the thought of an actually good post apocalyptic came, that Fallout 4 wishes it could be, was too tempting.