Badger Regdab is just a lube. It's a good airbrush lube IMO (best of the ones I've tried), but i doesn't have any effect on tip dry if applied to the needle. Iwata superlube does have some anti-tip dry effects, but it's short lived (washes off with a couple minutes of painting), and isn't nearly as good as the Badger stuff as an actual lube.
That Rustoleum stuff I would not put on any of my brush internals, as I'd be very worried about it contaminating the paint. Sure, it repels water, but how will it stand up to alcohol or any of the other possible paint solvents used to flush or thin? Will it wear off into your paint purely mechanically, especially when applied to smooth non-porous metal? No idea if it'd actually be any good or not, but I wouldn't be willing to risk any of my brushes to it.
Might be worth sacrificing a cheap brush to find out, but IMO such an experiment is better done by a more experienced ABer than a beginner. A beginner who's still figuring out their first brush will have a harder time parsing signal from noise in the results, and there'll be lots of things they won't know to look out for yet.
For a total newbie, best things you can do about tip dry are:
1) Make a habit of checking and wiping the needle frequently, whether you're having tip dry or not.
2) Practice building good "air on, paint on, paint off, air off" muscle memory. Getting that order wrong, even by a fraction of a second, exacerbates tip dry issues, as it allows a tiny bit of paint to be squeezed out onto the tip where it can dry before you pull the trigger again or be dried by the initial blast of air when you press the trigger. If you're doing this a lot without realizing it, you can end up building a disc-shaped stalactite of dried paint on the tip very quickly.
3) Polish your needle. As a beginner, stay away from anything hard or aggressive that could actually change the needle taper if done wrong. Just use cloth or paper towel and some fine polishing compound to carefully buff the micro surface.
