Where do you live that compost is less available than graphene? I'd love to move there, it's a wonder material that seems close to magic and I'd love to use it for my tech products. Where I live, there are absolutely zero risks whatsoever of running out of compost even if we converted all disposed food to graphene - but were very much lacking graphene, especially of the cheap and large scale variety.
They produce graphene from burning stuff. Where do you live where most things that burn don't contain carbon?
Turn things to graphene that otherwise would just be garbage.
You have enough compost? Send it to countries where deserts destroy farmland.