So, you don't like "central banks", but you still want a centralized party to control the currency? Otherwise, you need blockchain. Blockchain is just a consensus mechanism around data entries. If you want "just a virtual currency", bitcoin is that.
Find a way to do that and you'll do very well. Right now, the only way to do that without trusting a central authority IS with blockchain tech, that's what it was designed for and why it actually became a thing that's stuck around for the past 13 years.
You can't have a trustless, decentralized currency without certain styles of blockchain tech. Otherwise you're just once again trusting a central authority with control of a database containing your balance.
A key problem to solve is how to create a reliable source of truth for the currency. If not a traditional bank or ledger built on distributed consensus, then you're into the territory of inventing something new. It's a hard problem but I'd love to see it.