This is a crazy idea but I will say it anyways.

One of the bosses could be the Andrewsarchus king. He is 10 times the size of a regular Andrewsarchus and he lies in an an island called Andrewsarchus isle. There is a cave there too but a spino or Rex can fit in it cause there are bats

Snakes bugs and Andrewsarchus inside though the Andrewsarchus fight the cave dwellers and you. So the artifact in there was out there long ago by the only Andrewsarchus that survived going in there. It is called the kings cave and the king artifact which can be used with 3 other artifacts to get to the king. Then you go in with a powerful army and fight if you kill him he drops a crown. You put that crown on your head (it’s stronger than ascendant flak) and you can tell Andrewsarchus what to do. So you can lead a army to the Andrewsarchus cave and take it over. That is it for the Andrewsarchus king idea

This is based off research I have done about both ark and prehistoric animals-lava