K.I.S.S.
Large Kids play bucket filled with water, place propane bottle in water, a weight on top to hold it down and keep upright. Not dangerous, not hazardous, inexpensive, no power required. Can run 2 3/4” burners on a 20lb bottle till it runs out and maintain 50 psi outlet pressure. If you want to keep mosquitos from breeding a little common dish soap in the water stops that.