unable to export pool

[geole0]

I installed version 24.04 in a ZFS partition
I noticed that the software used comes from the ZFS-ZED package.

I now do another 24.04 installation in another EXT4 partition, I add the missing packages.
I can then easily access the data contained in the ZFS partition.

I now want to properly release the RPOOL so that it can be mounted without difficulty when I launch the ZFS partition (I reported a bug like this during the installation of zfs)

But this is impossible. Despite some internet searching, I can't find the right procedure.

zpool version
zfs-2.2.2-0ubuntu9
zfs-kmod-2.2.2-0ubuntu9

zpool export rpool
cannot export 'rpool': pool is busy

zfs get mounted -r rpool
NAME PROPERTY VALUE SOURCE
rpool mounted no -
rpool/ROOT mounted no -
rpool/ROOT/ubuntu_spel9m mounted no -
rpool/ROOT/ubuntu_spel9m/srv mounted no -
rpool/ROOT/ubuntu_spel9m/usr mounted no -
rpool/ROOT/ubuntu_spel9m/usr/local mounted no -
rpool/ROOT/ubuntu_spel9m/var mounted no -
rpool/ROOT/ubuntu_spel9m/var/games mounted no -
rpool/ROOT/ubuntu_spel9m/var/lib mounted no -
rpool/ROOT/ubuntu_spel9m/var/lib/AccountsService mounted no -
rpool/ROOT/ubuntu_spel9m/var/lib/NetworkManager mounted no -
rpool/ROOT/ubuntu_spel9m/var/lib/apt mounted no -
rpool/ROOT/ubuntu_spel9m/var/lib/dpkg mounted no -
rpool/ROOT/ubuntu_spel9m/var/log mounted no -
rpool/ROOT/ubuntu_spel9m/var/mail mounted no -
rpool/ROOT/ubuntu_spel9m/var/snap mounted no -
rpool/ROOT/ubuntu_spel9m/var/spool mounted no -
rpool/ROOT/ubuntu_spel9m/var/www mounted no -
rpool/USERDATA mounted no -
rpool/USERDATA/home_4903c3 mounted no -
rpool/USERDATA/root_4903c3 mounted no -
rpool/keystore mounted - -

umount rpool/USERDATA
umount: rpool/USERDATA: Aucun point de montage indiqué.

umount rpool/keystore
umount: rpool/keystore: Aucun point de montage indiqué.

umount rpool/USERDATA/home_4903c3
umount: rpool/USERDATA/home_4903c3: Aucun point de montage indiqué.

umount rpool/USERDATA/root_4903c3
umount: rpool/USERDATA/root_4903c3: Aucun point de montage indiqué.

zpool export -f rpool
cannot export 'rpool': pool is busy

zpool export -a rpool
too many arguments
usage:
 export [-af] <pool> ...

zpool export -af rpool
too many arguments
usage:
 export [-af] <pool> ...

Do you have some ideas? THANKS