The problem is that the game is not made from scratch.
Uses a plugin for physics called FGear(you can find on UE marketplace), which i cant sell due i dont own the rights.
Same for cars, they are licensed and will be changed on final/paid version for original ones due i have not planned buy the license for commercial use.
And same for other plugins like Ultra Dynamic Sky(UDS) that creates the rain, puddles, etc... or materials/assets like cones, containers and other stuff.
To be able to sell, i will need to invest lot of time to create a sample project without licensed assets.
Also i will have to write a large doc about how everything works and where is each thing or give support / resolve doubts.
And as said, i not have the time for all that sorry.