is there a way to extract from Bitcoin Core some stats about the totale number of wallets?
There's software out there that extracts this (current) information from
chainstate, so it should also work on a pruned node.
like an historical series of how the number of addresses with greater than zero balance evolved over time?
or just a snapshots of all the addresses balance at a given period of time...
This is more work, it requires processing the actual blockchain. There's software out there for this too.
But:
or to export the DB in CSV or something readable...
Blockchair did this already, and you can easily download it! It's slow, so I created a mirror. You may like:
I have snapshots going back a year (second link), or data dumps per day (last link).
If you only want to count funded addresses, I have data since September 2020:
total_number_of_funded_addresses.txt.
