Great question. It all depends upon what you want to do.
Do you want to play a version with a lot of content? Go play v0.89.8 "Seasons 1-4" and then v1.07.3 "Season 5" <-- these are both the "in development" versions, not "finished" retail.
If you strictly want a netorare playthrough, play the short completely optional and separate netorare route in v1.07.3 "Season 5" <-- this is the "in development" version, not "finished" retail.
Do you want to see 4k images and video with some additional content added of the first 20% or so of the game, all of it in AI generated art? Play Season 1 Redux. <-- this is the "finished" retail version, nothing more will be added to it. Further Season Redux versions will be separate downloads in the future.
Because of itch's rules, Redux has content Uberpie thinks could get it banned on itch.io. It is unpatched. If you want that content, Uberpie offers a free official patch to restore it. Download the official patch and install it within the Redux. See instructions in the installation spoiler.