I flashed an Ubuntu iso onto my external HDD and now I can’t use it

I used Balena to flash an ubuntu iso onto it. I am trying to install ubuntu on my external hdd to use on my windows laptop through a vitriol machine. Following instructions online I did that but the memory of 500Gb disappeared and left me with 3mb or so. Now I googled a solution to undo that and get back the partition on the HDD but my hard drive does not even appear in my file explorer anymore. My laptop does recognise it as it shows up in devices but I cannot view the storage or file content.

Thanks for reaching out. Try seeing if this matches your scenario and using the steps documented in this post Etcher broke my USB stick … or did it? to fix your device.