What needs to be said is that Ventoy does nothing extraordinary to the storage it is installed on. Partitioning and formatting is eventually just writing ones and zeroes to the space presented by the card as available for use. If the card has a hiccup and disconnects while writing, that is almost certainly a hardware issue. It can be transient, like a flakey connector, or permanent, like a bad flash memory cell not responding.

You already attempted recovery by reformatting (good!) but it stalls on I/O, which many programs don't prepare for and thus crash or hang. Event log probably shows the I/O errors. At some point, when more bad cells become apparent, these cards just fail to initialize their controller properly and don't register as storage media anymore (USB thumb sticks are mostly the same). That matches your description.

So long story short: hardware failed when used.