At the margin, S-risk work in AI is more important than x-risk work³

If you aren't extinct you can try to solve S risk. If you solve S risk but go extinct the same can't be said.            

Current AIs are capable of suffering

I think AI works largely by imitation. My mental model is that it is capable of performative tasks without the attached subjective experience. An AI will tell you that it is suffering if it thinks that's what you want to hear; it will just as likely say the opposite if it thinks otherwise.

While I find it plausible that AI can get to the point that it experiences what we would consider suffering I don't think we're at this point yet. I don't see compelling evidence that can be attributed beyond an LLM just predicting the next token.

If animals continue to exist in a post-AGI world, animal suffering will not persist

 

Biology doesn't change just because AGI is introduced as a new technology. While there are certainly advances that could reduce pain and suffering (e.g. lab grown meat) it seems implausible to me that animal suffering just ceases.

Besides, there are going to be people who insist on raising animals the conventional way who may be unconcerned with the suffering caused by factory farming, etc.