Hello, I was thinking that I might want to transfer my TSW 3 account to PC (For better graphics and performance) and I was wondering if this was possible without loosing my routes?
No, you can't transfer between platforms. You would have to buy TSW3 and all your routes again. The only exception is the XBOX store version which allows you to install on both PC and XBOX.
...the only option is to transfer your liveries or scenarios uploaded to Creators Club by downloading them again. But as already said PS4 and PC are two different platforms, which need their own license, even if it's one and the same game.
There's an exception to that is that if you own the Microsoft Store version of TSW 3 for Xbox and PC then you can simply transfer them over both ways. PS4 and PC versions are different.