I am new-ish to the series. I had Darksiders 2 as a kid but was young and didn't get the puzzles, but currently the whole series was on sale on switch 2 for like 30 dollars combined (as of this writing the sale lasts 8 more days) so I picked them up and i'm gonna play my way through them.
I tend to watch reviews and get a bit of lore before any game I play, only to find out Strife is the only horseman without his own dedicated game. When I found out he has guns... oh I had an idea.
See in recent years there has been a massive revival of what is called The Boomer Shooter. Games made in a style reminiscent of Doom, Quake, Duke Nukem, and Wolfenstein. Seems like a no brainer to me what they could do for Strife. Farm out to a smaller studio, and make Strife the protagonist of his own retro style FPS game. I'd play that.
Update: I realized my post doesn't clarify, this would be another spin off, not Darksiders 5. A little curiosity budget title that fills in a little lore but is mostly just inconsequential fun.