I have bad news for you, OP. Perhaps there is no safe and decentralized alternative to the bitcoin. Each currency has its creators, which directly negatively affects decentralization. Bitcoin is the only one of its kind and, in fact, there is nothing to replace it.

I will assume that Monero stands out from the rest of the crypto currencies and looks better than the rest due to the development of the project by the community, not the team, as well as mining on video cards (POW), which allows ordinary people to contribute to the existence of the project. What favorably affects the dispersal of capacities, in fact, this is decentralization.

I don't think ETH is close to the bitcoin (perhaps close to the coinmarketcap in terms of capitalization and current price), and Cardano is also not the best option in terms of decentralization.

Do you believe in the future of Cardano? Okay, so be it. It is not so much faith that is important here, but facts. And in fact, at the moment, this project has nothing to brag about in terms of decentralization, despite Hoskinson's statements.