In public utility we only did deployments on Fridays after 5PM

There's a bifurcation in best practices.

For industries that serve customer bases that are down-cycled on weekends, the dominant effect is "Deploy on Friday to minimize customer disruption chance."

For industries that operate with a 24/7 uptime expectation, the dominant effect is "do not deploy on Friday so you don't have to pay for your expensive software engineers pulling extra hours on a weekend. Much better to have disruption while the folks most qualified to fix it are in-house and alert."