I was going to post genuine advice, but this post is so ridiculous I realise it's not worth it.
You are living in cloud cuckoo land and only listening to advice that suits your agenda.
Good luck with your 6 week training schedule.
My puppy number 3 didn't sleep through the night until she was 4 or 5 months old.
Puppy number 4 wasn't toilet trained during the day until 4 months old.
Neither could be left home alone until they were at least three months old. And then it was only for very short periods of time.
I have also had rescue dogs - one was 7 months old, the other 9 years old. Both had incredible separation anxiety to begin with and would cry if I went upstairs without them, let alone left the house.Again they took months, not weeks, to settle in and be able to be left.
As for this forum having an outdated view - I would argue it's the opposite. When I was growing up, dog walkers and doggy day care didn't exist. People went to work and left their dogs home alone for 8 or 9 hours a day. Or going further back, dogs were turfed out to wander the streets until their owners returned.
People on here actually care about the welfare of the dog and put their needs first. Rather than indulging selfish people who think just because they want one, they should get one.
Also, what is a professional breeder? If by that you mean someone with a breeding licence, that counts for nothing. Time and time again puppy farmers are linked on here who have licences. It doesn't mean they know what they are talking about when it comes to giving behavioural advice. Of course they are going to say it will work out for you. They are after your money.
I'd also be concerned about breeders who still had 10 or 12 week old puppies left for sale. The vast majority leave at 8 weeks old. At the very least, I hope it is coming fully vaccinated by that age.