How do blockchain nodes find each other?

Question

bitcoin

I figured out almost everything already, I'm worried about the technical details. There are a large number of nodes (both complete and incomplete). Miners solve the block and send it to other nodes. How do they recognize these other nodes? Keeping a shared registry somewhere is kind of against the idea, broadcasting is somehow stupid. How is it solved?
Or vice versa - I install a local wallet, it must be synchronized with the blockchain (download it in full). How does the wallet understand which nodes to download from? Where do you find addresses?