Yup, Krown is a great product. Along with my 2019 Passport I own a 2007 Element (my daily) which I've owned since day 1. I Krown my vehicles regularly and have no corrosion or rust issue as a result, see proof in attached photo. I just undercoated my Passport, removing the plastic and tin covers before applying. I'm now waiting for next dry, clean non snowy day to take her out, The luxury of owning multiple vehicles. For daily passport drivers in the salt belt, I recommend you wait unit the spring or summer to undercoat. A good couple of rain storms should be enough to wash away the salt from the undercarriage.
I've had pretty good luck with Fluid Film in the past. I spray it on all kinds of things around the house. Usually have some around and when occasion arises that I'm underneath vehicle I just spray. Not very thorough I know but I appreciate the difference it sees to make. Lasts a long time also. Never used Krown but hear good things.