I want to learn about Web3 by open source, which project should I choose?

I want to learn about web3/etherium/blockchain/Defi/solidity by participating in open source, which project should I choose?

I work with data engineering, I have always learned from real projects, I have the theory, now I want a project to practice, to learn how web3 works.

The idea is to know the fundamentals, for example an engineer who programs in python, but has already programmed in C, that is, he knows what is behind python.