I’ve been using river for some low volume stuff. I love that I can add a job to the queue in the same db transaction that handle the synchronous changes.

Glancing at it briefly, I like the Workflows feature. I'm a long time Sidekiq user (Ruby), and while you can construct workflows pretty easily (especially using nested batches and callbacks in the Pro version), there really isn't a dedicated UI for visualizing them.

Also wanted to say I thought this problem has already been solved by River.

Although seems like OP references a Python library rather than standalone server, so would probably be useful to Python devs.