No one engages in bot content and many completely block it.

There were a lot more during one of the big Reddit migrations but they don’t work.

Communities need engagement and you don’t get that with bot cross posts.

There are whole instances dedicated to mirroring Reddit. However a lot of people on the fediverse oppose such features, on my home instance eg. lemmit is filtered out of /all stream. https://lemmit.online/

They exist. In some communities they may work but IMO a lot of times they hurt community engagement, since no one really wants to reply to an autogenerated OP or join a community that's a wall of empty bot posts.

A huge thing that real posts have but bot posts do not have: comments notify the OP and thus have a good chance of getting a response. The bot communities almost never get comments, and even if they do it's extra rare for them to get a reply.

If I didn't care about human-to-human comments then I wouldn't be here or on Reddit, I would just use RSS feeds, or the Google news feed.

This already exists, I have seen it used before, don't know any exact repositories though. The reason it's not really used is because it's pointless. What are you trying to achieve with it? Your community won't look more active if it has more posts with zero upvotes and zero comments all made by the same user.

Hiding posts from bots will also hide posts from this bot.

Keep in mind that not everyone here uses Lemmy, so a Lemmy feature isn't a good defense in a federated world like this.

Yes, it exists, but that practice is generally frowned upon and discouraged (at least by me)

It exists and some Lemmy communities operate that way. It’s not a good idea at all in practice. For example one community mirrors a tech support subreddit. It’s utterly pointless engaging in that community because the person asking the question will never read your answers. You can’t bootstrap a sense of community.

Reddit is astroturfed to hell, I prefer my posts to come from humans rather than companies trying to game system for financial benefit.

It's easy to make one. But why would you want that?

As time goes by and more and more people join the Fediverse, I'm sure some niche comms will start taking off. I don't like bots mirroring content from somewhere else, even as a help. In fact, I will immediately unsubscribe from any comm that starts doing that. And I'm sure many people also would.

https://fediverser.io/ is the project. https://alien.top/ and https://fediverser.network/ are the instances running it, but only alien.top is doing (some) mirroring.