Can I reduce two ffmpeg commands to one?

I want to find black at the bottom of the video and take that frame as an image.

Currently, it is done with two commands.

1. ffmpeg -i input.mp4 -an -filter_complex "crop=y=in_h/2:h=in_h/2,blackdetect=d=0.03:pic_th=0.99" -f null null
// output
// [blackdetect @ 00000253dd5d4880] black_start:40.5405 black_end:40.5739 black_duration:0.0333667

2. ffmpeg -ss 40.5405 -i input.mp4 -vframes 1 -vsync vfr img.png

If black is found in multiple frames at 1st command, I repeat 2nd command many times.

Can I reduce two commands to one?