hi friendly members
I need a GPU for a charting software, it stated requirement as follow:

Windows 10
Minimum of 1920x1080 display resolution ¹
Video card with a minimum of 1 GB memory supporting OpenGL 3.3. Ideally, a relatively modern one (released within the last 4 years).
16 GB RAM or more
SSD for Bookmap data folder with 100 GB of free disk space
Intel Core i7/AMD Ryzen 7 (or equivalent) or better. 4+ cores. ² Able to stay above 2.6GHz consistently. ⁵

This is my current CPU spec, which doesn't have have any GPU. Can I know what type of GPU suitable for my motherboard?

Processor AMD Ryzen 5 3400G with Radeon Vega Graphics, 3700 Mhz, 4 Core(s), 8 Logical Processor(s)
BaseBoard Manufacturer ASRock
BaseBoard Product B450 Pro4
PCI Express 3.0 x16 Slot (PCIE2)
Thanks all

That GPU just for office productivity work is much overkill is it not? And Im not sure if OP has min 700W PSU to run that GPU.

@satori plan to run multi monitors
@babylon52281 forgot to mention about my budget, hope to get one card that is below or around 1k
@tristanx using bookmap and multi monitors
My PSU is only 500W

Seem my budget of 1k, only can get Radeon RX 6600, 8GB, 8x, 4 outputs.
Is this good enough?
Thanks all for the reply.

SAPPHIRE RADEON RX 6600 GAMING 8GB GDDR6 - RM900
MSI RADEON RX 6600 ARMOR / MECH 2X 8GB GDDR6 - rm900
PowerColor Fighter AMD Radeon™ RX 6600 8GB GDDR6 - RM865
ASUS Dual Radeon RX 6600 8GB V3 - rm827

GTX 1600 is 1 gen earlier than RX 6000, the drivers will EOL much sooner. Better to get a later series GPU even tho gaming perf is less coz the point is not gaming anyways.

The RX6600 sounds good for your case.
3400G only provides x8 for external GPU. 

If you really have budget, go change the MOBO before you want to get PCIe-based GPU. All the GPU now running on PCIe 4.0. While your MOBO only support PCIe 3.0, unless you don't mind of not fully utilizing the full potential performance from your GPU.

Recommended System Specifications for Heavy Use (MBO, high-resolution full depth data, e.g. Rithmic or some cryptocurrency providers):

OS: Windows 10
Display: 1920x1080 ¹
Video card: Modern card with minimum 1 GB memory supporting OpenGL 3.3 (Requirements increase with additional/larger monitors)
RAM: 32 GB (More if running other software in the background) ³
Storage: SSD for Bookmap data folder with 100 GB free space (More if you want to keep more data loaded e.g., leave Bookmap running for a week)
CPU: Modern Intel Core i9/AMD Ryzen 9 (or better) with 8+ cores ² (consistent 3GHz+) ⁵
Internet: Stable connection, 100Mbit/s minimum, low package loss
Mouse: Middle button required for one-click trading add-on
.NET Framework: Version 3.5 or higher