Very interesting take on this in the novel Death's End by cixin lu
For instance, Greg Egan seriously considering the nature of 2+2 universe, that is, two space, two time dimensions: https://www.gregegan.net/DICHRONAUTS/DICHRONAUTS.html (Don't miss the interactive simulation: https://www.gregegan.net/DICHRONAUTS/02/Interactive.html )
He's got a few others, too.