Podman – stores the data when pulling and building the image and this location is defined by the parameter imageCopyTmpDir
root@pve-pdman-01:~# podman info | grep imageCopyTmpDir
imageCopyTmpDir: /var/tmp
root@pve-pdman-01:~#
root@pve-pdman-01:~# export TMPDIR=/tmp
root@pve-pdman-01:~# podman info | grep imageCopyTmpDir
imageCopyTmpDir: /tmp
root@pve-pdman-01:~#