Here's a tutorial to get people started with a ball and paddle game in Unity. It's pretty basic, but it was helpful when I first started using Unity.

https://noobtuts.com/unity/2d-pong-game

Kinda late now but here's a nice physics tut for Godot too. Get up and going in about 15 minutes.  Plus Godot is only like 30 megs ;)

Still have to add the reverse vectors on collision but that's pretty easy.

http://kidscancode.org/blog/2017/12/godot3_kyn_rigidbody1/