Is "endorsing nazi content" a drama that can die down?

In this media environment? Yeah probably. We’ve all gotten very good at forgetting inconvenient facts.

Should it go away? Probably not.

How do you earn money with Substack if you don’t paywall anything?

You use it more like a Patreon. I don't think it's easy, but it works for at least some people like Scott at AstralCodexTen (who arguably has some paywalled essays, but it's extremely rare and I doubt it's the reason why almost anyone is subscribed to him).

So content is free, and readers can make a donation?

Yep, something like that.