A dog will not usually knowingly mess in their crate and definitely think the solution will be getting up in the night to let out so hope that works for you. How did getting up at 4am work?
Also am with the others in spreading out his food more in the day into smaller meals more often. At that age I was feeing my pup at 8am, 1pm and 6pm with some of his food allowance also fed through treats so each meal was pretty small. Mine have 24 hour access to water - it's not in my room at night (where my dogs sleep) but my dogs have been known to go downstairs at night and have a drink. My pup also woke at night sometimes just for a drink when he was tiny - yes he had to wake me up to do this but I'd prefer that than a dehydrated dog and it's very rare that they want water in the night.
My pup is now 17 weeks and he has his last meal at 6pm. We tend to be out for a walk until 8/8.30pm where he has treats and quite a bit to drink when we get back. He sleeps from about 9pm and I wake him about 11pm for a last wee etc and he sometimes has a bit more to drink then and he sleeps through now until 7.30/8am - he's a whippet so not a huge dog.
I've never used pads or anything - I basically resigned myself to waking in the night and watching like a hawk all day so that every toilet incident would be outside as consistency is key in their learning. He had a crate in my room and I'd hear him get unsettled or cry if he needed the toilet and I'd carry him downstairs and take him outside with no interaction at all - just toilet and back to crate.
A baby monitor could help you as that way you'll hear him as he gets unsettled and needs the toilet Usually a dog will never want to mess in their crate so will cry first before going to the toilet in there. That way as he's ready to sleep through longer, he will and you won't be waking up unnecessarily.
However, now he's got used to a nappy/pad etc, you might have some work first to undo this so his natural instinct to not mess in his crate kicks in again. I think just getting rid of all the pads and never let him use one again should work for this. Every toilet incident should be outside. I didn't treat for going outside as the treat can interfere with their fully emptying their bladders - they learn to look for the treat as soon as they start going. Just a good boy and I'd say the word I wanted as the cue word for going to the toilet. I treat a lot for everything else and say good boy too so that he definitely got the idea it was a good thing to go outside.