python 3.9 with pip3 install wand pillow PyPDF2 pwgen pikepdf installed on 2021-04-22
ImageMagick 6.9.7-4 Q16 x86_64 20170114
Ghostscript version 9.50
problem
apparently no garbage collection in local /tmp/ folder on machine. Tons of files like /tmp/magick-11240N0pYJKPD4KyY, 47MB each remain. Redirect using --tmp <directory> does not help.
Workaround
Lower DPI
Give a temporary directory path(with enough space) as parameter where the imagemagick temporary files will get dumped => !57 (merged)