What are your thoughts on this idea? (GTA VI vs Online and their relation to GTA V's Ending)

GTA Online solidified Ending C as the canon ending, with Michael appearing in the Mansions DLC and Trevor being referenced in Smuggler's Run and The Contract. A lot of people are wondering how GTA VI can have a more grounded story, considering it exists within the same universe as GTA Online, where events like The Doomsday Heist took place 9 years earlier. My idea is that GTA V's endings created separate timelines. GTA Online is set in the world where Ending C is canon, but what if GTA VI took place in a universe where either Ending A or B happened, resulting in a more grounded storyline? It would be a more interesting way to actually utilize the multiple endings of GTA V, rather than Ending C just making the other two pointless.