Welcome.
If Suzuki deliberately tried to create a bike that could get as dirty as possible in as short a time as possible they succeeded with the latest generation. I considered a belly pan but wondered if it might trap moisture and make it more difficult to clean. Ignoring that sensible thought completely I started polishing the headers and because of that I decided to go with the mudflap plan, this is the 8th or 9th iteration. My bike is 4 years old this year with 28k miles.
It started with a Pyramid fender extender to which I added an ebay long mudflap - these tend to be too soft and flexible so I had to put stiffeners inside and at the same time extended it further. The mudflap is attached to the extender with nylon screws.
The good news is that it keeps the header and oil filter clean the bad news is that it looks a bit naff. I suspect that the sides of the engine are getting dirty from spray coming off the sides and top of the front mudguard but when I tried a couple of ideas to prevent that it blew the top off my naff-ometer.
As far as I can tell the main area for rust is the the gear change shaft as it enters the engine and the various bits of gear change linkage. The brake hose distribution thingy under the headlamp needs watching too as does the rear shock inside the spring and the cheapie spring clips on hoses. It goes without saying that any screw head immediately wants an unholy tryst with salt water.