Hey, I’d go with something like a GTX 1650 or an RX 6400 for your setup. Both are solid for charting software, support OpenGL 3.3, and fit your B450 Pro4 board just fine. I had a similar setup with a Ryzen 5 2600, and a 1650 worked great for light workloads without breaking the bank. If you’ve got a bit more to spend, the GTX 1660 Super would give you extra power for future-proofing.