Another update: I just got a text saying my outage is resolved. But... you guessed it, still experiencing speeds way below what I pay for. They scheduled me a tech appointment, but between these consistent "service interruptions" and being pressured to upgrade my plan mid-outage, I think it's time to cut ties.
I highly, highly suggest that anyone who experiences these issues complains to the FCC and find another ISP (if one is available. A common thread in these complaints seems to be a lack of alternatives, which is somewhat the case here as well). Cox is clearly committed to their shoddy and shady business practices.