Record Only 1st Screen in a case you have two with FFMPEG
Command:
timeout 5 && ffmpeg -y -f gdigrab -offset_x 0 -offset_y 0 -video_size 1920x1080 -framerate 24 -i desktop -f dshow -i audio="Virtual audio desktop" -c:v libx264 -crf 20 -preset ultrafast C:\Users\ipalamarchuk\Desktop\output.mp4