Yes, I think he should add wrestling as one of his skill sets. Because we know he can kick pretty well but what if someone doesn't give him the space he needs. And that is surely going to happen when he faces someone who has really good grappling skills. A good grappler will always try to close the gap to score takedowns and try to go for ground and pound. If he has wrestling skills he will be able to defend himself in that situation far better. And if he does not consider learning wrestling, he better stay on his feet in the ring because if he goes down it will be trouble for him.
Well, it is up to him to add something to his arsenal and the best way to do it is to add wrestling, but it is still OK if he will go to a Striking route just like Israel Adesanya, he will need to polish his takedown defense to ready himself with an opponent that has Wrestling moves, but yes takedown still has a huge score for the judge, but I think he already polishes with his striking with punch and kicks because he comes from kickboxing so he is really ready when it comes to that aspect, but when it comes to a well-rounded game inside the octagon.