SCS Software began overhauling the entire audio engine. In 1.39, you’ll notice:

You don't have to pay $200+ for everything. Here is how you get the "full" 1.39+ experience legally for less:

: A new launchpad was introduced, allowing players to adjust game options and manage profiles before even loading the main game. Sound Improvements Turbo slider

All DLCs purchased on your account (such as map expansions or cargo packs) will automatically work with version 1.39 if they were released on or before late 2020 Key DLCs functional in 1.39: Going East! Scandinavia Vive la France ! Road to the Black Sea Heavy Cargo Pack Incompatible DLCs: Newer expansions released after 1.39, such as (released April 2021) or West Balkans (2023), will not be accessible in this older version. Major Features of Version 1.39 ETS2 1.39 Update Release

Euro Truck Simulator 2 (ETS2) version 1.39 was a major update released on November 3, 2020

A complete overhaul of these trailers, making them ownable and highly customizable with various chassis, bumpers, and lights.

Wait for Steam sales (summer/winter) where you can buy the "Map Booster" bundle or "Essential" bundle for 70-80% off.