The Parity codebase was taken over by new maintainers and turned into OpenEthereum: https://github.com/openethereum/openethereum
However, writing and maintaining an Ethereum client is an exceptional amount of work with very little benefit, the primary OpenEthereum maintainers recently announced they would stop maintaining OpenEthereum and would start pouring their energies into an upcoming client called Erigon. https://medium.com/openethereum/gnosis-joins-erigon-formerly...
Erigon is a much better client.
There are so many things you can get wrong when writing a new Bitcoin implementation.
I'd stay very far away.