Nostr .wine is pay-once-to-write so it basically filters out spam from the get-go for "global" content viewing or single relay browsing. You're basically paying once to be part of a cleaner feed. Nostr .land is similar in that respect but also does more, so its a subscription. One main thing it does is help protect your replies from spam, if you set it as a public inbox. It also works for your DMs.

As far as those affecting reach, it really depends on what client your followers are using. Some find your notes, regardless of what public outbox you are sending your notes to. Others look on a static set of relays. If you have a lot of iOS users who follow you, putting these bigger paid relays as a public outbox is a good idea.

Broadcast sends a copy of a note to any relays that will connect with you & accept it. Fork is like a fancy copy/paste for adding thoughts/ideas/context to other people's notes while still crediting the original author. Different than a quote note in that it's more for collaboration. I think only Amethyst has that feature & displays it correctly though lol