Slide in Jack height

Or something similar to H/J extenders bolted to extend legs.
https://www.adventurerv.net/happijac-jack-lift-extenders-p-43011.html

Can the jacks be adjusted down? A picture may help your responses.

IMO jacks should never be used "maxed out" or close to maxed out. Use blocks.

We have a Ford F350, a tall truck. We use the plastic leveling blocks we use to level up the truck when we are traveling to also unload the camper when we take it off. Lighter than wood and serves two purposes with one product. We carry two bags so we always have a few extra.https://www.amazon.com/Camco-Leveling-Blocks-Hydraulic-44505/dp/B00480BWCI

^This.
And if it feels tippy, like shaky or unstable, that's because the jack legs are maxed out.
If you need 5" of lift then put the camper on something stable like 12x12 blocks or an entire timber or cut a couple plywood rips and run them transverse and screw the blocks to them (where you back over the plywood when getting under the camper. Then the blocks can never kick out sideways.

wood blocks under the jacks.. If the tc is level, it hasn't tipped over yet, another 6" in the air is not going to magically make it tip over.