My almost universal experience has been to simply do a Git revert and let the CI pipeline do its thing. Pros - It's simple. Cons - It's slow, especially in an emergency.

My last job had an extra layer of security. As a .net house all new deployments were sent to Azure in a zip file. We backed those up and maintained FTP access to the Azure app service. If a deployment went really wrong and we couldn't wait the 10-20 mins for the CI pipline to process a revert, we'd just switch off the CI process and FTP upload the contents of the previous last good version.

Of course, if there were database migrations to deal with then all hell could break loose. Reverting a DB migration in production is easier said than done especially if a new table or column has already started being filled with live data.

To be fair though, most of the problems I encountered were usually as the result of penny pinching by management who didn't want to invest in proper deployment infrastructure.