Hi and welcome to the forum.
Since you are in Indiana (47452) and have a number of serious issues I'd call Winnebago Customer Service and make an appointment at the Factory in Forest City, Iowa. I realize it's 600 miles away from you. But getting everything fixed and diagnosed at the factory is by far the best way to get your complete list fixed AND have the piece of mind you need for the future.
Summers are super busy at the factory - so don't be surprised if you can't get an appointment before October or November.
I have a 2017 gas Class A and I made an appointment after the purchase before I even had much of a list of problems. We just returned from our May 1st appointment. But for us it's over 1000 miles to the factory. We felt it was well worth the trip.
Winnebago customer service also provides phone tech support. Call them with the Cab Fan Fuse question and they'll direct you to it. Same for the powered steps. Or check with "Kwikee" the company that makes the power entry step.
Slide work - the factory is by far the best. But other RV repair shops (probably not a dealership) with lots of experience can handle this issue.
You're not far from Elkhart, IN and that area is the HOME of the RV industry. Not many Winnies made there but slide companies, step company, etc are all right there. I'm pretty sure all would offer service or have a expect tech in the area.
The soft floor doesn't sound good. I'd talk only to the factory about this issue.
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad