It's not ruled out entirely, but it does seem very implausible.
God of War: Ragnarök was released with a bang two weeks ago and has received almost exclusively glowing reviews: we gave it a solid 10 in our review. Ragnarök tied up the story that began in 2018's God of War, and sadly there doesn't seem to be any continuation of the story in the form of DLC.
It's the director himself Eric Wiliams who is coming out with the sad news in the Kinda Funny podcast. It's worth pointing out though that he's not ruling out there being some DLC but that it seems very unlikely.
In short, he says that the game is very big and that they poured everything they had into it, so a potential DLC is not something we should expect. Something that should come as no surprise though as Santa Monica Studios doesn't usually release any expansions for their titles.
However, we certainly haven't seen the last of Kratos, but when the next game might come is very unclear at this point. What turns it might take after this is also very much unclear.