Yes. There are quite a few bots out there and they are here to scam. On Damus, you can block accounts, but the bots will likely spin up new identities. Another strategy is to use paid relays instead of the default relays. This helps to increase the signal / decrease the noise.

Yes.

Those are spam bots.

Nostr is working on several stuffs like paid relays, PoW etc. to combat the bots problem.

Hopefully something positive will come out soon.