well, if you want to plug something that's actually open: https://mastodon.social/@kagihq
Bluesky isn't really an open as they claim it is (it still requires their central server. meanwhile Mastodon/etc are actually federated).
About this suggestion (my personal opinion, not my staff opinion): I'm not really what the benefit would be of this over all the various fediverse software like Mastodon/misskey/etc. They've already reinvented the wheel, plus there are so many choices already, what exactly would Kagi bring to the table that those haven't already done.
Now Kagi hosting a Mastodon instance or some other fedi platform. that could be an interesting idea, although obv it gets complicated about: what happens if you stop paying or your credit card gets declined or something. You lose access to your main social account.. not great either.
But yeah, this feels like reinventing the wheel when 50 other people are already reinventing their own wheels.
And in the end it only makes sense to make something that's compatible via activitypub so it can federate with all these others platforms. and they already do that. so yeah.