There are a few lower cost items you can start off with.
On soft surfaces, place a large foot under each stabilizer foot. I use 3/4 plywood, cut 6" x 12" (can use under a tire for leveling too). This spreads the weight over a larger surface area on the ground.
A few hours after setting up and the next morning, go around and give your stabilizers a quick adjustment to tighten them back up. Remember these are stabilizers and not levelers. Do not over tighten. Lifting causes a loss of stabilization.
Using a product like X-Chocks between the tires. This device jams the tires and keeps them from wanting to wiggle/roll.
Adding an additional stabilizers. Place one set in front of the axles. This will help take out some of the bounce from frame flex.
The above items are the easy low cost items to start off with. There are other more costly options. Many do require drilling and bolting on accessories.
Sample hardware mentioned above;
https://www.amazon.com/X-Chock-Wheel...s%2C181&sr=8-5
https://www.amazon.com/RVGUARD-Trail...s%2C139&sr=8-3