Think you’re going to have to accept a little dent to his ego as collateral damage.
He needs telling straight, this is a deal breaker - you need to slow it down and be patient or it’s not going to work. I’m not in the business of mediocre sex, I want a partner to blow my mind. And more importantly - I want a partner who WANTS to blow my mind. If that’s not you, then that’s a shame as we have a lot of other good things going for us, but I won’t settle for an unfulfilling sex life so I need you to listen and work with me without ego, or if you can’t/won’t then let’s move on and find someone we’re more compatible with.
You can Dress it up a bit more like ‘we/us/compatibility’ rather than ‘I need you to xyz’ but the end result needs to be him recognising that he’s not doing it for you, and he needs to start again.
With my DP, the faster he tries to go the longer it takes me, so he’s learned that if it’s not working out, we stop, he tells me it’s ok, we’ve got all night, we’re not in a rush, then we start again.
So rushing doesn’t actually help - more haste less speed and all that.
Next time your fella tries to hurry things along just stop, say I’m not really feeling it, and leave it there. As long as you continue and he gets his pleasure he has no incentive to do better.