Since you will be using it for light gaming and media, I'd suggest getting a 1st or 2nd Gen Ryzen CPU, because you won't have to look for Motherboards that support 3rd Gen Ryzen from the box.
A Ryzen 3 is completely fine for media and light gaming. A 2nd Gen APU might be perfect in your case, but it really depends on your definition on 'basic gaming'. If you want to play Indie Games and very light 3D Titles, a Ryzen 3 2200g along with a cheap A320m Motherboard is perfect.
If you are looking to play some heavier titles, like Fortnite, R6S, PUBG, etc. You should consider getting a Ryzen 3 1300X or Ryzen 3 1200 along with a 1650 Super (New)or a 1050ti (Used).
But it really depends on your budget. You could go all out and buy High-End stuff, that you won't really need.