I'll preface my comments; by first stating that I'm an "insurance guy".
I've seen just how bad things can go wrong...
That 5000 pound rating has been put there for several pretty good reasons:
1. the hitch itself perhaps can't survive more than that.
2. the mounting system may not survive more than that.
3. your RV's frame might not survive more than that
4. your RV's braking system and chassis dynamics may not survive more than that.
5. your cargo carrying capacity might not "permit" even that much weight
As an example: my RV has a 5000 pound rated hitch also; yet I can only tow about 4200 pounds before I'm exceeding GVWR limits.
So my setup is weghing in at just over 3000 pounds.
(I don't like to stretch the limits...
But you do what you have to do: it's your rig!