Probably also 0% 😄 But coins will get lost, I think we can’t do anything about this? 🤷‍♂️

If by deflation you mean price movements, then I‘d say we could look at the PC/chip market.
Don’t know if we would call it optimal, but it’s a working market, still.
Even if prices drop ~50% every year or two, or computing power doubles every year or two for roughly the same price.