You need the correct .dat file and you need to configure the \ventoy\ventoy.json file.
Instructions are on the site:
https://ventoy.net/en/plugin_persistence.html
I suggest you download the .dat zip file
https://github.com/ventoy/backend/releas...images.zip
and extract the correct one for debian
e.g. one ending in persistence.dat - such as persistence_ext4_512MB_persistence.dat
When you configure the ventoy.json file correctly, you select the ISO and Ventoy will prompt you to select the .dat file for persistence.
If you still have problems, post the ventoy.json file here + pictures.
Instructions are on the site:
https://ventoy.net/en/plugin_persistence.html
I suggest you download the .dat zip file
https://github.com/ventoy/backend/releas...images.zip
and extract the correct one for debian
e.g. one ending in persistence.dat - such as persistence_ext4_512MB_persistence.dat
When you configure the ventoy.json file correctly, you select the ISO and Ventoy will prompt you to select the .dat file for persistence.
If you still have problems, post the ventoy.json file here + pictures.