Just, a noun. (?) [closed]
I can't seem to find an answer to whether the adjective "just" has ever been used as a noun in the history of the English language.
Just can be a noun, and has been used that way since Middle English:
The prophetis..that bifore teelden of the comynge of the iust.
Wycliffe Bible, c1384
(See more modern translations of this passage.)
This is similar to how we often talk about the rich and the poor.
However, in your sentences it is just an adjective.