If I understood correctly, the queue implementation in the blog post holds a transaction while an operation is in progress.

I see the advice to make it as short as possible, but why can’t we update the status column to, say, “processing” and avoid potentially long transactions at all?

Did you test with fillfactor < 100 on the queue table? With HOT updates, status changes can reuse dead space without creating new index entries, which seems like it could significantly delay the onset of the death spiral?