2 options: some clients let you choose which relays show where. You could turn off public relays for global requests but use them to supplement everything else.

Another option is to look for public relays with spam protection. #[11] runs nostr.mom like this.

Lastly, if you do make the hop to paid relays, make sure you checkout nostr.wine and how we are bridging the gap with our filter relay. Read me here: https://filter.nostr.wine