That's a very difficult question!
The 5600x is a nice CPU though and if you got the money and don't want to change your CPU in a year, then spending the money now might be worth it for you!
About the graphics card:
Instead of "matching components", you have a "possible fps range depending on settings and racing situation" for both CPU and CPU, which are different for each game.
So for example:
rFactor 2:
- alone on track in the sunshine:
-- CPU = 120-170 fps depending on shadows, track details and reflection levels
-- GPU = 80-250 fps depending on all settings
- racing in the rain and sunset with 40 AI cars:
-- CPU = 60-100 fps
-- GPU = 30-180 fps
How much the settings influence the CPU and the GPU and how the racing situations differ in performance is different for each sim.
Now most people mean by "matching components" to have "medium/high settings with some ultra for eye candy on their specific monitor resolution and good amount of AI cars or online opponents".
It's important to know that settings barely make a difference for CPU performance, but make a HUGE difference for the graphics card's performance.
While the racing situation makes a big difference for the CPU performance but not necessarily a big difference for the graphics card's performance.
Anyway right now there are basically 3 graphics card available to match a 5600x depending on the used resolution:
3060 ti
3070
3080/90
And respectively the AMD counter parts of course. 6700xt, 6800 and 6800xt. Or even a 6900xt.
So please tell us your resolution or the used monitor/vr headset.
The CPU is more important for simracing anyway though since you can always lower settings and sacrifice "eye candy" to get a fluent image.
But if your CPU isn't strong enough to maintain solid fps, making things look ugly will only give you a small boost.