Elsewhere in this thread people linked to devices that did exactly this

https://usb.brando.com/usb-cassette-mp3-player_p01122c035d15...

https://pt.aliexpress.com/item/4000181019563.html?gatewayAda...

They receive a mp3 (or other format) and output sound through the magnetic stripe (and also to headphones if you don't put it in a walkman)

Not sure why you'd want something like this. Imagine writing a book on paper, but instead of letters you're writing the binary representation of each letter. Wouldn't it be easier and more efficient to just use the paper as intended?

Just use good metal tapes, you'd be surprised with the quality (read: hard pressed to notice it's a tape). Plus, whatever circuitry you're using gives analog sound an extra bit of personality (though this isn't always for the best).

That would give you relatively little playtime. A standard 90 minute tape cannot hold all that much binary data.