Terms of what cryptocurrency is and what blockchain is, Cryptocurrency is not blockchain but blockchain introduced cryptocurrency and there is no cryptocurrency without blockchain or blockchain without cryptocurrency. So in a simple way, both are some way connected to which other. There is no cryptocurrency without blockchain and no blockchain without cryptocurrency.
The banks are no scared of crypto but they are just scared of the idea of decentralization of the financial ecosystem.
You got it all wrong. Both blockchain and all cryptocurrency stem from one source - Bitcoin. And blockchain was just a part of Bitcoin's protocol, but then startups started hyping it like it's some miracle invention that can fix everything, and people became confused about blockchain and cryptocurrency, they think that blockchain is the most important part of cryptocurrency or that crypto and blockchain are sysnonymous
There is no cryptocurrency without blockchain and no blockchain without cryptocurrency.
No, in fact many startups are trying to do blockchain without cryptocurrency. And this is the type of thing some banks are trying to do, they think that blockchain will somehow make them better.
Also, banks aren't scared of decentralization, because so far decentralization doesn't scale, even cutting-edge technology like Lightning Network wouldn't allow Bitcoin to replace banks.