I don't power wash with fluid film applied. I just wash without pressure, because, yeah, I think enough times doing that will take it off. I would think the fluid film plus regular rinsing would be a much easier path. How would you power wash with a week of January temps well below freezing...
No KDSS allows you to set the truck up to wheel hard which I do not do. But KDSS plus a modest lift gives you some still very nice off road capability and some great on-road manners as well.
Just get 2 or 3 cans of fluid film, use the red straw, spray it in every hole you can see and on the outside of the frame and be done with it. Takes an hour once a year. No biggie, my man. This is coming from a relative non wrencher.
I've fluid-filmed mine annually - it's a 2016 with 116k miles and although I'm not in as much salt as you, it's still here, and I don't have any frame rust. Point is, you don't have to be discouraged by the brand... just maybe a little more proactive because Toyota truck frames don't have a...