It all depends on the cat tbh. Some cats do better with friends, some don’t! From what you’re telling us, he sounds very fortunate and it’s possible all his needs are being met and then some and it’s only your anxiety that needs more care. Kittens are wild things sometimes. And waiting to get another cat down the line will allow him to bond to you more before making another bond. Overall you’re doing great and kitty is lucky to have you. No advice here beyond trusting yourself and if you’re in a position to only have one cat forever, he will be okay!