The timeless mod hasn’t been updated to the new mod format yet. If you absolutely want to use it now, you have to right click and select “Enable Legacy mod”. If that option is grayed out it means it is already enabled in normal mode.
Disable the mod and right click, “Enable Legacy mod”.
The mod will modify all your vanilla vehicles but can’t modify mods in the new format or the USA DLC. For this you need to wait until I have converted the mod to the new system.