Comment by sneak

The NS record wins. The data in WHOIS is just non-operational metadata, WHOIS is not used for lookups.

Which server gets used is usually randomized from the set of possible ones. Same for which of multiple A or AAAA records are used to connect to.

Us sysadmins would love to be able to specify weights or round robin or retries (like with SRV records) to move load balancing and failover to the clientside but for whatever reason browser vendors have rejected this for years.