another protocol 😭 although i like the flexibilty of being transport agnostic. i still think about some kind of complementary remoteStorage sync mode over wifi / bluetooth

It's a silly argument really. It inherently acknowledges that their problem is already solved by Nostr, but since they themselves are unwilling to simply use that and onboard people to their own relays and/or clients, the solution is not good enough for them and their peers. Maybe it's a practical joke by an xkcd fan? 🤔

Yeah, so my idea (and rough plan) was for kosmos.org users to have anything they post to the Nostr relay be synced to their storage automatically, so then other apps could go and cross-post content from there (in addition to just having a syncable backup and potential cache there, too). As you say, the transports can be much more agnostic, as long as the original content is signed by someone's key.

you mean any (their*) relay or a kosmos relay?

I meant the/a Kosmos relay, but it could also be a more generic program that follows pubkeys on multiple relays. From an operator's point of view, it's not fun having to connect to arbitrary other relays via WebSockets, and you have to build in a lot of fault tolerance to deal with timeouts and such. Another option would be to do this directly in a Nostr client, of course, but then it wouldn't work with arbitrary clients. However, the RS-enabled client can sync all the events posted by other clients and back them up to RS once received.

Yet another option for more technical users would be to do it with a dedicated sync program on their computer. For example, I automatically sync my Nostr events to my laptop in a background job once an hour. Would be rather easy to just post them to RS from there, too. That said, I still like the original idea of it being as easy as flipping a switch in the account settings, so that I as a user don't have to worry about any of it.

my solution was to setup a personal relay before posting anything, so that i can export things easily if needed. i resist using most nostr apps because i don't feel like i have my data in the end, and much prefer the patterns of remotestorage where i know there's at least a copy always accessible in a place i control

One would hope that most Nostr apps respect your relay settings, so that your personal relay is that place.