Automation has taken over most of my work, so why am I still sitting in the office for 8 hours?

I design automation systems to handle repetitive tasks. One recent project was a workflow for reaching out to YouTube creators who make indie game videos. It finds active channels that fit certain criteria, checks their content, drafts a personal email for each creator, sends a small number of emails from our studio inbox, tracks replies, and shows the results on a dashboard. A few years ago, this work would have taken me hours each day. Now the workflow does most of it, and I mainly check that it is running correctly and fix problems when they come up. I am glad the system saves time, but it has also made me think: what should a workday look like when automation handles many of the tasks that used to fill it? Sitting at the office for eight hours when the main workflow is already running can feel strange. For people who have automated a large part of their job, what do you do with the time you save? Do you take on new projects, focus on improving the systems, or find that your workplace still expects you to stay busy for the full day?