WuMing on Nostr: Forgive me for trailing off a bit here. I have had problems for missed messages on ...

Forgive me for trailing off a bit here. I have had problems for missed messages on iris web from day one. Missed in the sense I post from my mobile and messages and their replies are not visible from my laptop. And vice versa. Since relays don't cache other relays, the way mastodon do, people I am in a conversation with must post on the same. Or their must sync from mine. I currently post on 11 (10 at times) relays. Why is not that enough? Is there a preferred relay, from where all my messages are collected from, and others are just for redundancy in a post-nuclear catastrophe world (not that it would matter by then).