I understand how frustrating that is, and despite hatching for literally over 20 years, I had a horrible time hatching turkey eggs when I first started out with them. Like no joke, I was getting about a 0-10% hatch rates with my first few sets. It was not nutritional, the birds were prime breeding age, they were not closely related and some completely unrelated, and fertility was 90-100% so the toms were doing their jobs. It forced me to nail everything down to a science in order to get poults to hatch. I had to buy new hygrometers (I love Govees that you can use to monitor temp/humidity with your phone). That is when I started doing a modified dry incubation and it has been a game changer, not just with turkey eggs but also chicken eggs.
But sometimes, no matter what you do, some breeds/varieties just don’t hatch well. We set a few clutches of eggs from a certain pair of birds this year and ZERO of those eggs hatched. It is due to a number of reasons, mainly the hen isn’t a spring chicken anymore and it getting up in years, and the line has just been kept pure and uninfused with fresh blood for so long, we had to infuse it with another line to try to salvage it. That may not be your case though if your birds aren’t older or the gene pool is bigger.
I store eggs in a spare turner as I collect them for the incubator so you can’t turn them too much I don’t think. And I think the sportsman turns every hour. But if the eggs are developing all the way to lockdown and then failing to hatch, it is likely a genetics issue at play or humidity. Usually too high of humidity will affect my hatch rates, and as long as you don’t incubate below 20% humidity, too low of humidity is probably not the issue. If it has been humid there, high ambient humidity may be causing the humidity in the incubators to be too high, even when running them dry. I would monitor the humidity in the rooms and in the incubators with some Govees. I get mine on Amazon. I have heard of people having to run a dehumidifier in the room with the incubator because their ambient humidity is high, so with as much rain as you have had, that could be possible.