I have (2) full size wool and cotton futon mattress stacked on top of each other directly on the floor with NO wood or metal frame underneath. They are under $200 a piece so $400 for the two. They can’t be broken and can be taken outside and hoses down/ bleached/ spot cleaned with bleach solution and a rag. They make futon covers out of all kinds of materials including microfiber. Futons can’t be broken but they can be unzipped and the stuffing pulled out. A little nylon stitch job over the zipper area and that’s not a worry anymore. It’s made from duck canvas so it crazy sturdy. Just a quick warning...it’s a very firm sleep after they settle but they make mattress toppers that make them soft as you like. We had to go this route because my son would throw a temper tantrum and try and pickup his spring mattress and throw it around. Futons are as dense as lead so all he can do is kick it around!
The look of disappointment on his face the first time was priceless!

There is a company near here that makes a bed called the rough rider. Mine have yet to break it. It is made of 2x6 lumber.

My son mainly sleeps on his crash pad I always find him there lol.

I have thought about using 2 boxsprings to elevste the bed, to create the illusion of full size.

Do you know anyone good with woodworking me and my boyfriend made a wooden framed bed you can use bolts instead of screw for sturdiness and also thicker wood. Im sure there are designs or ideas on pintrest. Hope i helped.