It's good that you are researching all of this
You've had some really useful information from good people who breed as responsibly as possible and have a lot of experience - definitely take everything they've said on board
I've never bred from my dogs and never would, even though like you, I had a 'romantic fantasy' about having pups from my first cocker when I first got him. Basically because I loved him so much and he was so utterly beautiful in my eyes... He came from a line of very successful show dogs and who's breeder had been breeding, showing and judging for years and is still today (11 years on from then) absolutely passionate about cockers. The reality was, that even with all this experience behind his breeding, he was actually a little too tall for his breed.
However, for me THE biggest reason I wouldn't bred from my dogs is that I couldn't cope with loosing one of them if it went wrong. If my bitch wasn't spayed and I decided to put her through having a litter and she died or suffered serious medical complications or stress - it would because I'd done it to her, and that's not something I can cope with.
Aside all the other risks, I also wouldn't breed because I can't cope with the thought that I couldn't guarantee that one of the pups wouldn't be joining the thousands of very healthy dogs of all ages - both cross breeds and pedigree dogs - that are in rescues and pounds throughout the UK through no fault of their own, waiting to see if they will ever be offered a home or waiting to be destroyed in mass euthanasia sessions.