I'm using more paid relays than public ones, didn't help the feed today, though.
Discussion
Paid relays are not essentially better than non paid. Latency matters the most in lag free Nostr UX.
Relays should be curated as latency can vary by location.
Try a mix of popular public relays(ensure you get most notes) and paid relays (reduced spam - can be set to global only), but ensure the one's you connect to are < 100ms Latency for you on nostr.watch
Over 3g with 2 relays, iris snort, looks ok. (some missing events, but wip...)
Is there a max relay recommendation as a client?
Generally around 10 with any bad performing ones removed seems like a good number.
Will the client readd them if performance of one relay improves?
The client won’t. You might want to make a note of them to re-add them later. Are you using Damus?
What is the average cost to run a "good" relay?
Check out nostr.watch where you can check things like recent uptime, and latency #[3]