3 of 4 added 920 characters in body
exiftool -q -r -if '$MIMEType =~ m{^video/} and
                    $ImageHeight < 1080 and
                    print "$Directory/$FileName\0" and 0' . |
  xargs -r0 echo rm -f

Would remove all videos whose Image Height is less that 1080 pixels (if you removed the echo) in the current directory, recursively. That assumes file names are (properly) encoded in UTF-8 (though see the -charset option for other charsets).

Instead of piping to xargs rm, you can also store in a file (> list), to do some inspection on that list first:

xargs -r0a list ls -ldrS

If it looks fine:

xargs -r0a list rm

Or store the information in JSON format so you have all the relevant information in an easily readable and parseable format:

exiftool -q -r -j -if '$MIMEType =~ m{^video/}' \
  -ImageWidth -ImageHeight -VideoFrameRate -MIMEType . > list.json

Then review that list, and delete based on some criteria:

PERL_UNICODE= json_xs < list.json -t none -e '
  for (@{$_}) {
    unlink $_->{SourceFile} if
      $_->{ImageHeight} < 1080 || $_->{VideoFrameRate} < 60

(note that I found that for FLV files, it was Videoframerate instead of VideoFrameRate, you may want to watch out for this kind of inconsistency).