I'm pretty sure Cory Barlog said he had a pentology of games planned for Old Kratos, of which the Norse duology were the introduction. I don't think it's a coincidence that Athena featured in GOW 2018 but not Ragnarok. In the comics that detail Kratos in Egypt, we know Athena appeared to him alongside an Egyptian God, telling him he was fleeing from his destiny and that he couldn't escape forever. So my theory for the next GOW after Ragnarok kinda takes elements of both of your proposed theories but ties them together with the enlightened Athena (recall that she ascended after her death in the second game), Atreus' quest to restore the Giants, and Kratos' acceptance of Godhood at the end of Valhalla. My personal theory is that with the games having shown Kratos accepting his past and beginning to forgive himself for the Greek era, the only way to challenge that - to truly show Kratos' growth - would be to bring Athena back in some way. So a nice little theory is that Atreus, having exhausted all Norse options to restore the Giants, begins to research other iterations of the fissure that Odin was obsessed with beneath Asgard. His research leads him to the newly formed Roman empire and he departs to seek guidance from Minerva, Goddess of Wisdom - who, of course, is Athena in disguise having rebuilt the Greek pantheon under the Roman monikers. She is responsible for the fissures, as part of a plan to eliminate all Gods but herself, and tricks Atreus into working with her to achieve this goal. Meanwhile, back in Midgard, Kratos and Freya face off an attack by an otherworldly army, which is followed by an emissary from the Roman pantheon who invites the new Norse gods (including Kratos) to join the Roman pantheon in an alliance or be faced with invasion and destruction of the Nine Realms. The new Norse Gods reject the invitation to join and instead war is declared between Rome and the Nine Realms, but as Kratos kills the emissary, he reveals that Atreus is now their prisoner. Leaving Tyr and Freya behind to ready the realms for war, Kratos and Mimir embark on a journey to rally support from other gods (similar to Tyr's journey as seen in the panel from Odin's vault in GOW 2018) and rescue Atreus. Meanwhile, it turns out Minerva has been working with Sindri, who has become hateful of all gods since the events of Ragnarok and is being manipulated into helping with Minerva's cause by promising both Kratos' and Atreus' deaths if he builds weapons for her. After all, they created a weapon that could kill a God during Ragnarok (the Draupnir Spear) so why couldn't he do it again when paired with an ascended goddess with access to infinite knowledge? Kratos arrives in Rome and his reformed character is put to the test when Athena reveals herself as Minerva. They fight but Kratos loses, and Minerva escapes with Atreus now *actually* her prisoner, having originally simply been working with her to try and bring his people back. That's just a rough idea but it would seem to me the most logical next step in Kratos' journey is to challenge his newfound acceptance by showing that his past is still affecting his present, and how will he react when someone who knows him better than anyone else returns.

No freakin Atreus as main character in the next game! Not him.

I want Kratos in Egypt, after that i will be fine with him anywhere