Discard the Django app. Rewrite as a Kafka consumer, perhaps? (Note that the PHP Kafka libraries are immature, so it's probably best to choose almost any other language?)
Preserving backward compatibility with the existing schema should be carefully weighed--it's feasible to rewrite all usages, so they should be sprayed with something uppercase during this evaluation. We might even be able to write a SQL view that transforms our new schema into similar-enough fields to satisfy the usages...