Ok, we’ve had loads of puppies over the years. Calm down about everything and stop expecting him to behave like the books say - they are all different. I don’t agree with the three hour in and out of a crate thing - you need to go with what your puppy wants - three hours is too long - the cycle between awake and sleeping during the day will be much shorter, maybe an hour awake, 20 minute nap, hour awake etc.
Crates are fine to use as a safe, secure space for him, but are don’t use it on a schedule. Put him in the closed crate if you are unable to supervise him - cooking, answering front door etc. Otherwise leave the door open. He will get to the point that he will take himself in there for his nap as that is where his comfy bed and his toys are kept. This will take a while though, young puppies usually will just fall asleep wherever they happen to be at the time - if possible on top of you or one of the children. You get to read and watch tv a lot!
They need a routine to an extent. Getting up times, meal times, toilet times need to be reasonably consistent (but don’t make a rod for your own back by sticking to dinner at exactly 6pm for example - 10mins either was is fine). However, don’t kill yourselves trying to stick to it like glue - dogs are pretty flexible and as long as they know where you are and therefore feel safe they will go along with most things.
Puppies will run around like nutters, chew stuff, interact with you (walk around doing your chores but chat away to him as you do so, he should tag along - he just wants to be near you) and then they suddenly crash out. Fast asleep for 30 mins or so (just leave them - do not wake them up!) then up again and off they go again.
Garden is good, lots of new stuff, new smells, etc that will tire him out mentally too - he is much more likely to sleep after a good half an hour sniffing about outside, more so than inside. If your garden is too big to let him off out there, then I would suggest a puppy pen - Amazon sell them - put it on the grass, with a bowl of water and in some shade (be very careful with the hot weather - they overheat easily) - and then sit outside with him and he will happily sniff the grass and snuffle about. Children can supervise this too. He may bark - he is talking to you - chat back, so he hears your voice. I talk total drivel to mine - about the news, the birds, my shopping list, what a pretty boy he is - he needs your voice.
Remember he is absolutely NOT biting to hurt you - he is just trying out his teeth, tasting things and has an instinct to chomp the same way teething babies do. There is absolutely no malice there are all, dogs do not have any malice in them. Dogs/puppies are just love in a rather mad and energetic bundle. Do not punish him for it - he is just a baby that has not got his Mum with him anymore. You have to be his Mum for him now, let him know the behaviour you want from him gently. If you watch puppies together with other dogs, they chomp too hard and the other dog squeals at them and they stop. A simple taking away of the your hand and a high pitched “no!” each time will stop it. I have never had a a puppy that doesn’t understand this after a couple of days if you are consistent.
Make sure he HAS got stuff to chew on. I buy baby toys for puppies. The most popular one we have had been Nuby teether - all the puppies love it - it makes a fab noise and the chew bits on it seem the right size shape for small puppies. Obviously will not be any good once he is bigger or for a big breed though.
Also Yak Milk bars are great for them (do NOT get those hide chews from the shops - incredibly dangerous - lots of dogs have died from them) - just watch as they get them small - when down to a few cm’s microwave them for 45 seconds and they puff up and go crunchy and you can then let the dog finish it off).
Tried to give loads of suggestions there - hopefully they will give you some ideas of how to manage things.
Please don’t cry over him, he is just a baby, he just wants to be with you and be loved - he needs you to look after him and love him.