Yes, it is only kind 1 at the moment. This was done in order to allow greater reach of videos since all clients support kind 1
Discussion
That approach won't help the adoption of kind 21 and 22 in those apps nor the growth of your app. Why not use a hybrid model with a NIP-71 first approach? I'm trying not to be salty here, only constructive (and yes biased) how we should embrace other events kinds to grow Nostr more broadly on the long-term. There is so much more than only kind 1 stuff.
nip71 needs to support parameterized replaceable events, so videos can be changed if we want it to be properly utilized for a youtube-like or other video dominated platform where creators have greater control. Otherwise, it's no different from kind 1 besides less adoption. Unless, I have completely missed where replaceable events are supported, despite no mention of it in the spec?