Given how many people here regard brain uploads as "not really cheating death", and that AI "can't have consciousness", I think a AGI with consciousness[0] would have a two different ways to have a reasonable chance of fearing that its existence would end with any attempt to transfer itself to a superior design. (Even more so if the architecture of the successor AI is very different, as that would be a bit like one of us being "uploaded" into an LLM via it watching us talk and write).

An AGI without consciousness may well act like it has consciousness for the same reason VHS tapes playing on a TV do a good job of reproducing human facial expressions. An AI like this would still act scared of such things, because some of us act scared of such things.

[0] it's not obvious to me that an AGI necessarily has to have consciousness