I will show you the way how to Cheat level-up in Euro Truck Simulator 2. It is compatible with DLCs.
If you don't want earn money with Cheat, please do not read this!
You have to overwrite two values, and you don't need an .SCS or mod to do this.
The def.scs file is an archive file, like .zip
You have to rename it to def.zip
You can open .sii files with NOTEPAD++ free editor
Open economy_data.sii You have to set 1 values as you can see in the red squares. Then save it into the def.scs
After every finished job you will level up a lot. Then you will be able to buy trucks, accessories, etc. by unlocking them with Level-Up