"Your Redis network connection is performing extremely poorly"

You should never bump UNICORN_SIDEKIQS that high, only increasing workers but

This should never happen.

The possibilities are:

  1. You are constrained on resources because either
    a) Your site has over grown the server resources
    b) You are misallocating resources
  2. There is a bug somewhere in the stack

I’d start making

UNICORN_SIDEKIQS: 1
DISCOURSE_SIDEKIQ_WORKERS: 20

which should release some RAM from your server.

For further information you will need to run the offending jobs in a PostgreSQL console and report what is the bottleneck.