Anyone interested in a security first cryptocurrency you should check out Tezos.

Tezos uses proof of stake with a bond requirement that should solve the nothing at stake problem. The two big issues with proof of work is that it uses massive amounts of energy and unless you're the top coin or among the top 5 the chances someone will easily 51% attack your network is high.

Also Tezos uses a formal programming language for its smart contracts that should help reduce certain types of bugs.

It's an interesting project and as a disclaimer I own some.

The project had many growing pains but is on its feet now and I think that their first on chain governance vote went through recently, meaning the codebase can be updated in a decentralized manner.