I have no clue as to which RV and chassis you have, but all chassis makers specify what type grease they recommend for their build. Pick a grease that meets these specs and STICK TO IT. Problems cam come from mixing greases so choose one that's been around for a while and you can get easily. Same goes for gear lube and even oil, antifreeze, and trans fluid. I've had good luck with Grease Gun In A Can for things like door latches, hinges and steps. You seem to have found a good slide seal lube and you may need specialized lube like high temp brake lube for brake S cams and special lubes for Pac Brakes.
A lot of the "recommendations" for a specific lube is a lube company that pays a builder to recommend their product. If there's special reasons for that they should say so and usually do, but the difference between a chassis grease and a grease for a tongue jack is just about non-existent. Using WD-40 is an issue because WD-40 is really a water displacing fluid not a true lubricant. In reality though, regardless what you use, regular use of something will put you MILES ahead of many RV'ers who never lube at all or who depend on a technician who doesn't do the job at all and still charges you for it. A simple look at the zirks after a "service" will show you how often that happens.
Pigman & Piglady
2013 Tiffin Allegro Bus 43' QGP
2011 Chevy Silverado 1500
SMI Air Force One toad brake
Street Atlas USA Plus
