To add onto this, I think that this two prong approach can really streamline the relay experience:

1. NIP-65/Gossip for intelligently finding what relays your follows posts are

2. For those who also want to automate what relays their posts are sent to (ie: very casual users), clients could use an API like https://api.nostr.watch to select a handful of relays that optimizes for high uptime and non overloaded relays