I managed to change the language without dowloading the game again.
So in case someone needs it :
→ In the launcher find the game properties
→ Click the Browse button next to the install location
→ Go in the __Installer folder
→ Type "cmd" in the address bar
→ Run the following command
Touchup.exe install -repair -locale en_US -installPath "C:\Program Files\EA Games\Apex\" -autologging
You can replace en_US with the wanted language code and the game path in case yours is different.
→ Wait a bit for it to process in the background
→ Profit