All POSIX compatible shells have their quirks and differences because the common POSIX part is rather small, so you will need to learn them anyway when switching from one to another. Fish is not that different from them (to much less extent than something like nushell) and it benefits from having less ancient baggage.
We still don’t know how much of Oblivion they actually recreated, considering it’s rumored to be made in UE5 which is a completely different engine. I’m most worried about open world and “immersive” elements such as Radiant AI and NPC schedules, proper wildlife AI, etc.