Interesting... Well, when I was reading "Isekai" this post really caught my attention. I'm glad that the world of anime is catching your attention more, as a big fan of this niche (as you may have already noticed 😅) it is a great pleasure to be able to guide you in this. 🤗
Considering everything you've mentioned about the lore and what you're looking to incorporate into your video game, I recommend that you don't just focus on one genre, like fantasy in this case, but also explore others genres like science fiction, for example. It is worth highlighting a detail about Isekai, and that is that it is a demographic, not a genre as such; it is like the description of the specific audience or niche to which that type of work/series is dedicated.
The genre itself is fantasy, which has a lot of subgenres and demographics such as Isekai. Depending on your tastes or preferences, you can delve into fantasy or dark fantasy; the more you explore, the more interesting things you can find. There are the typical generic stories of the typical "hero's journey" where he defeats the Demon King with his Harem and all that; but there are also other stories that are worth seeing because of how different they are.Examples of this can be Dungeon Meshi, Frieren, and even Witch Hat Atelier.
When you mentioned time travel to the past with memories of the future, it sounded more like science fiction to me, but there's something similar in the Isekai demographic that might interest you. The anime is called Re:Zero and is a potential masterpiece, also known as The Best Isekai of all. One detail worth mentioning is how different it is from other Isekai series due to its plot and characters. It features time loops and similar elements that are quite captivating. Something that might be useful is the topic of magic as a tool to apply certain spells or curses for players looking to experience something similar to "time travel".
Well, you're talking about Neuralink technology and AI, so I don't know if that's your preferred genre and if I'm wasting my time writing all this (I hope not). 😅
I hope I was able to help you with something.