Improving sex life in the early stages of the relationship.

Hoping for a bit of help from the sisters! I've been seeing a guy for almost 6 months. I really like the guy but the sex is..... meh. I have asked him multiple times what he likes, or what can I do that's just for him, but he always just says "I like everything". I don't know what everything is though, he won't tell me haha! I've tried to initiate different positions but it always ends up back to missionary (which is fine!) and he ends up doing all the hard and fast work, gets tired and then we just end up cudling until we both fall asleep. I'd love for him to say "I need a rest, how about you do so'n'so...." which I have tried to then take over and do all the work but he's just too exhausted. He's not an unfit guy so I just don't get it..... 🤷‍♀️
I should also add that there is definitely a nice amount of foreplay at the start!
Don't get me wrong, there are times that he finishes, but it's always after the hard and fast missionary, but more often than not, he gets too worn out.
What can I do to help his energy levels last longer, or at least get him to communicate what he wants/likes?