The SkyFeed Builder will get support for video-related blocks (like only including videos or searching their alt text with regex) next week or so, videos (incl. captions) are already being indexed in the SkyFeed database.

I just re-enabled most personalized SkyFeed feeds (like OnlyPosts and Mutuals), performance is looking good so far. All feeds are however still cached for 10 minutes on average, so please keep that in mind when it seems like new posts aren't appearing on it.