If you don't want to go the block route, JT StrongArms or BAL Lock Arms are amazing for adding rigidity, they turn the feet into upside down pyramids which are significantly more stable than a tower which is what lone landing legs/leveling jacks look like.
2019 Dutchman Kodiak 293RLSL
2015 GMC 1500 Sierra 4x4 5.3 3.42 full bed
Equalizer 10k WDH