I'm not sure where your expectations come from to be honest.
Who do you know who is running ryzen 56 and RX6600 GPU and getting great performance in DCS at medium/high settings?
I'm sorry if this isn't helpful, but while your CPU and GPU might represent decent value for money, neither are high performers.
So the best thing you can probably do is to accept that your hardware is not underperforming. Then it might be easier for you to use lower settings and keep the game playable. It doesn't need to be on high settings to be very immersive. A few years ago we were all enjoying games in 640x480.
