The different approaches are interesting:
Built by Berlin developer Sebastian Vogelsang, who previously launched the Bluesky client app Skeets, Bluescreen is an upcoming app that will focus on videos posted to the Bluesky social network. Similar to his Instagram alternative Flashes, which is also in the works, Bluescreen is being built quickly thanks to Vogelsang’s ability to reuse some of the same code from Skeets.
And:
Reelo represents a larger effort at building a TikTok-like app that appeals to Bluesky users, but unlike other efforts, it’s not just a layer or filter on top of Bluesky’s existing social network. Instead, Reelo is developing its own stand-alone app on the AT Protocol. That means Reelo will benefit from the same sort of transparency and control over your data as on Bluesky, but it will be free of the limitations of building on top of Bluesky directly.
You can deploy an app that just filters BS for videos pretty quickly and cheaply but you run into limitations. Only one alternative is using the AT protocol, which is ambitious and potentially expensive. We'll see which approach wins.