OP reporting back, after some sleep.

To be clear, not looking to bash Delta, just trying to understand what to expect in LA. I was mildly annoyed that they changed my booking without telling me or my asking for it, but I'm over it.

Some responses to above:

* "Not because of Delta" was based on my (mistaken) understanding that separate PNRs led to the previous delay being irrelevant to the second flight

* I wanted back on my original flight because I was unsure that I could make it to the airport in time, I prefer Delta, and killing 10 hours in a private room with a bed seemed preferable to the same in LAX. At the time I made the request, I didn't know that my original flight had already been further delayed.

Now that I'm booked onward on a day with many possible ways to get home that day, SDC or SDS seems viable. At this point my worst case scenario is that Delta will cancel my 2nd ticket as a no show if I am not there in time.

My current thought is to wait until it's pretty certain that I'll depart at some specific time before calling Delta again. As long as they don't cancel me as a noshow, I think I'll get home....

Edit to add: now I see my 1st flight has been outright cancelled. Gonna be a fun day