The general approach is to do multiple migrations (add first and make new-code work with both, deploy, remove old-code, then delete old-schema) and this is not specific to Django's ORM in any way, the same goes for any database schema deployment. Take a peek at https://medium.com/@pranavdixit20/zero-downtime-migrations-i... for some ideas.
I still feel like Swift 5 (5.2?) was the sweet spot. Right now there are just way too many keywords, making C++ look easy again.
Similarly, I find Combine / GCD code far easier to write and read and understand, and the semantics are better than structured concurrency. I have plenty of production Combine code in use by (hundreds of) millions of people and it hasn't needed to be touched in years.
I wrote a hacky version of SKIP LOCKED using advisory locks and a recursive CTE before it was released for a job queue. It worked splendidly, along with the transactional semantics of a proper database. I’m surprised more systems don’t realize they need it.