nothing is ever totally new
My guess would be that quantum tunneling memory is going to be amazingly similar to current pre-existing technology, but now has quantum in the name for easy access to more venture capital funding. The future of digital neural networks is good old fashioned analogue technology, but with rebranding.
Basically it is trapping electrons like an eeprom (2 transistors, so that individual bit can be flipped) or a flash memory cell (1 transistor, large blocks of bits need to be flipped - designed this way to cram more bits into less physically space).
Oh and SLC flash is where a single bit is stored in each cell (2 states - more than half full with electrons or less than half empty with electrons)
MLC is where 2 bits are stored in each individual cell (4 states - more than 3/4 full with electrons, less than 3/4 full with electrons but more than 1/2 full with electrons, less than 1/2 full with electrons, but more than 1/4 full with electrons, or less than 1/4 full with electrons)
TLC is where 3 bits are stored in each individual cell (8 logic states)
QLC is where 4 bits are stored in each individual cell (16 logic states)
And every year the size of the cells gets smaller and smaller and the number of electrons stored in each cell gets less and less and the error correcting codes to compensate for the continual data loss at the lowest level bigger and better.
At the end of the day it is going to be a tiny patch of insulating silicon holding a few isolated electrons, working in a similar way to rubbing an insulating balloon on your head. It is basically a temporary static charge, but in the case of eeprom/flash stored inside an insulator, and not on it's surface like a balloon does.
One problem with flash/eeprom is their limited write lifetime (pushing and pulling electrons into and from an insulated island eventually degrades the quality of the insulating layer and it does not work as well as it did on day one after manufacture) and another perhaps less well known issue is that the data (unless powered up and actively corrected) will eventually after a good few years being powered off just fade away (This depends on the temperature of the device when the data was written, hotter is better for long term offline storage but worse for Mean Time Between Failure, and the storage temperature when the device is powered off, the colder the better for long term storage).