sorry to rain down here but multi-device support is not a feature of metafeeds at all. It only realizes partial replication. It's equally important to grow the network but strictly distinct, all metafeeds are on the same device.

multi-device is only spec'ed but not implemented in what we call "fusion identities": https://github.com/ssb-ngi-pointer/fusion-identity-spec

also, the ngi team has nothing to do with planetary.