Looking to upgrade graphics as a first-time builder, don't know where to start.

Last year I built my very first gaming PC, and I'm looking to make a graphical improvement. Nothing too crazy, I have no need to play at 4k, but something so I can play a few recent releases decently. Here is my setup so far:

https://pcbuilder.net/rigs/515tnw/

I'm not sure if I need to get a GPU alone, or if there are other specific improvements I need to make as well. Any and all help would be appreciated!