None of what you reported sounds like I would ever take my bubs back to that groomer. I personally don't like the cage dryers and many good groomers don't use them for the reasons you describe. Many dogs get overheated, dehydrated and you are right, the only way to get them completely dry is if they stand the whole time. To be dramatic, there have been cases of animals dying in those type of dryers.
Your dog should
never be returned to you with any blood whatsoever! Occasionally a nail quick can get nipped but styptic powder should be applied and bleeding stopped before the dog ever goes home. I've never heard of a dog coming out with a bloody nose.
We take Sophie and Syrus to be groomed about every 6 to 8 months. Mainly because they do such a beautiful job getting all the hair out and they come back absolutely gorgeous, soft and happy. They only use hand-blow dryers. We had Sophie done right before surgery. With both ACL's blown she couldn't stand for more than 5 minutes at a time. They were able to work with her sitting most of the time and did a wonderful job.
How on earth did a groomer
accidentally break a Newf's tail??

Poor Bosco. These sound like horrible experiences for him. There are very good groomers out there. If you take him again I would encourage looking for one who has experience with the double coated giant breeds. And no cage dryers!
Our groomers charge from $60 to $80 (per dog) depending on what we have done from a basic wash and comb out to the full works with hair trimming around ears, paws, legs and chest. They have more than one groomer so for both dogs it takes them about 4 hours.
I totally understand about taking them to a professional. I do quite a bit with my bubs from brushing to washing regularly, but sometimes they just need a very good thorough head to toes from someone with all the proper equipment and patience.
Give that Bosco a big smooch on his big beautiful nose. Good luck in finding just the right groomer.