The launcher is fine as long as it works correctly, it’s a way of keeping track of updates much more easily than a website but ultimately you shouldn’t be having the issues getting UE4 installed.
Also, I would like to point out that your GPU will be an issue–UE4 can only use a single GPU, and in your case you have Quadros which aren’t designed to run games very well, so you may run into some issues due to that.