Dokotton, welcome to the forum. This is a great place to get and share information when you are working on your rig.
I cannot speak for the factory, but as far as doing work yourself I think that most, or at least a lot, of us would prefer to do the work on our own.
Again, I cannot speak for Heartland but I doubt that doing the work yourself would affect your warranty.
Disclaimer here, if you fixed something and that caused another part to fail, that may be a problem. Or if you screwed up what you were working on and made it worse it could be a problem.
Whenever my dealer did something for me I got documentation. I would ask for that. It could protect you down the road if it is documented with Heartland.
Peace
Dave