LogFAQs > #966966383

I do have a recommendation that fits most of those requirements, but I'm not sure if it counts as isekai. In Cage of Eden, basically a plane full of passengers (including the protagonist and his class on a trip) hits turbulence and winds up on a strange island filled with plants and animals that are long extinct.

It's made even stranger by the fact that the plants and animals all hail from different time periods, making their initial assumption of time travel seemingly impossible. They have to survive and maybe find a way home by grouping together, learning to trust one another, and of course often their greatest threat winds up being other people.