As with any add-on program, having too many objects displaying or too many actions occurring simultaneously will put extra stress on your sim and push it beyond what it can handle. As with all flight simulators, the important thing is to find a balance your setup can manage. That may mean turning down the settings (including GSX’s).
That said, agree with both @MikeB54331 and @jfoguet61, Couatl crashing is a symptom of MSFS CTDs rather than the cause of them.
The Windows Event Viewer will show a Flightsimulator.exe error just prior to a couatl64_msfs.exe error listed in the events log.