Automate what you would delegate anyway
A useful filter for deciding what to automate is asking what you would hand off to a trusted team member without a second thought. If you would happily let someone else handle a task with barely any instruction because it is simple and repeatable, that same task is usually simple enough for a tool to handle as well, often for less ongoing effort than training a person. I ask myself this exact question before handing anything off, whether the recipient ends up being a person or a tool.
This matters because the instinct to delegate and the instinct to automate come from the same place: you want the task off your plate without worrying about it. Running the delegation question first helps you separate tasks that only need clear steps from tasks that genuinely need a person's relationships or reputation attached to them, which tools cannot replace no matter how well built they are.
Try this today: list the tasks you would hand to a new hire on their very first day with almost no training, and check whether a simple automation could handle each one instead.