If you are doing a rename you should have it look for the new environment variable and then fall back to the old one if it’s not set. Log an error when that occurs, and then slowly go through and remove the old environment variables in your deploy code, then remove the compatibility code

sure but every other company looks to Meta, Google, Amzn, and others to see what they are doing, and then they mimic it, because Business Idiots are herd animals.