Let's figure this out...
Did you buy the DXS by itself, or did it come with an airplane/heli? If it came with an aircraft, which one? That matters because it will tell which profile the DXS is using. If the DXS is in its helicopter profile, then it will be a challenge to make it work with RealFlight with a wireless USB receiver. The DXS has four airplane profiles, with "Standard Acro 1" being the one most commonly used with RTF airplane kits.
RealFlight assumes the DXS is using the "Standard Acro 1" profile. If that's a safe assumption, then the next thing you need to do is select the correct Controller Profile for it. You can get back to where you select the Controller Profile two ways:
1. Press ESC for the ESC menu, and then choose Settings > Controller > Configure Controller.
2. If you have the legacy menu bar visible at the top of the screen, go to the Simulation menu and Select Controller.
That will take you to a screen like this:
View attachment 147009
The WS2000 will be identified at the top as "SPEKTRUM RECEIVER". You want to select the "Spektrum Receiver (DXS)" Profile. That should automatically handle any control mapping for you, getting the stick and switch inputs associated with the correct settings in RealFlight.
With that Profile selected, you can go into the Calibrate function. Follow the initial direction to center anything that can be centered - move the throttle stick up to center, the other stick controls should spring-center themselves, and move the three-position switches (B and D) to the center position. The proceed to the next screen where you calibrate. Move the sticks in the shape of "+" signs, not circles. You want to calibrate each direction of the sticks one at a time. While you calibrate the sticks, be sure that Switch F (rates) is in position 0 (up; high rates). You'll also want to move all of the switches fully back and forth a few times.
As you're doing the calibration, you should be able to watch the blue bars move all the way from the left end to the right end. If you're only seeing partial movement, that's another issue. Of course, if everything looks good, finish the calibration, and it should be working at that point.
If you don't see the blue bars moving all the way from one end to the other during RealFlight's calibration, then you'll have to check things at the Windows level. Close RealFlight, and run a program called "joy.cpl" in Windows. That's where you can see game controllers. You'll see SPEKTRUM RECEIVER listed in there too, and you can select it and drill into the properties for it. Within there, you can see if the sticks and switches all make things happen, and beyond that there's a calibration process. The Windows calibration process talks about Xbox-style inputs, but that's not really a big deal. You can just move things around on the DXS until you find the right one that Windows is asking for at the time. You want to teach Windows the full range of the stick/switch just like you did in RealFlight. Ideally that process will straighten things out. Then you can run RealFlight again, run RealFlight's calibration again, and then you should have success.