Yes, I was able to pay for relays without linking my ln wallet. But that may depend which client you are running on. (I’m on Damus)

Paid relays are keeping the spam out. You can pay using lightning, you don't have to add a lightning address to your profile.

A list is here but how much operational or how active I don't know. https://relay.exchange/

Also you can choose a free relay like nostr.mom that does better spam filtering. It has a very clean global compared to average. Disclaimer: I operate it.

https://nostr-resources.com/ https://uselessshit.co/resources/nostr

Sign up for nostr.wine. Add the main relay and follow instructions to add the filter relay. If using Damus, in the global tab, select hamburger in the top right and allow only paid relays. You can pay directly from a custodial wallet/ramp that supports LN such as cash app. Other popular paid relays...

I’ll put in another plug for nostr.wine. You add that relay and filter.nostr.wine with a couple parameters in the URL and it does automatic filtering and broadcasting to other relays that will make your experience more robust. It’s more expensive than others but still cheap in the grand scheme...

Best is to use the web browser iris.to im conjunction with getalby