Google do try and kill off standards from time to time. Killing RSS meant more clicks to websites, more trackers, more ads, more data. But a worse experience for the world.
I'm glad to see RSS making a small resurgence lately. We must protect it!
The AT protocol is interesting from a technical perspective - but largely does what ActivityPub was already doing. ActivityPub already has huge applications with milllions of users (see Mastodon, GoToSocial, PixelFed, Spectra/Video etc).
Join the Fediverse. It's cooler than Bluesky both literally and figuratively.
IMHO obviously...