Leave them there.
Pick them and make jam to sell at local Farmer’s Market. You will make money!
I would love to have blackberries on my (tiny) property. I have to go into the county forest to pick them.
My wife and I were shocked to find Walmart selling them in this area where they tend to be an extreme nuisance... But of course blackberry jam and pie is a favorite in our family, and when we were kids we did sometimes sell them by the roadside.
We have to be careful walking in black berry patches here in lower Alabama. Rattle snakes like to hide in them because of all the birds the berries attract. You won’t see me trapseing through a patch while the berries are in season...
“I would love to have blackberries on my (tiny) property. I have to go into the county forest to pick them.”
A suggestion: Get the thornless variety. They should be available at your local nursery.