> So instead of cash we would need anonymous physical (and digital) tokens whose value is not fixed, but is adjusted according to the interest rates.
So what you want is... cash. But cash from a separate currency. This is identical to what we had here in Brazil in the 90s during the Plano Real transition: the cash everyone had was in the Cruzeiro Real currency, but all the prices were denominate in URV (a "virtual" currency, which months later became a real currency called Real). The Cruzeiro Real was suffering from inflation at the time, but the URV was stable, so to buy something with a price of 1 URV you might pay CR$ 864,14 one week and CR$ 1004,68 the next week (source for these values: https://pt.wikipedia.org/wiki/Unidade_real_de_valor).
So what you want is... cash. But cash from a separate currency. This is identical to what we had here in Brazil in the 90s during the Plano Real transition: the cash everyone had was in the Cruzeiro Real currency, but all the prices were denominate in URV (a "virtual" currency, which months later became a real currency called Real). The Cruzeiro Real was suffering from inflation at the time, but the URV was stable, so to buy something with a price of 1 URV you might pay CR$ 864,14 one week and CR$ 1004,68 the next week (source for these values: https://pt.wikipedia.org/wiki/Unidade_real_de_valor).