I have tried several different things to set and follow weekly and daily agendas. Some have ended up being too detailed, too much work, and ultimately unsustainable. Others have been so minimal that it's hard to see what I accomplished on each day and in each week.
I've found that a good balance is to have a weekly agenda with a few high level goals, maybe 3-5. Then a list of 3-5 tasks per day. This is enough that you can plan the main things you want to get done each week and day, but not so much that it's overwhelming to track it all. It's a manageable number of tasks to track.
This sets you up for a sustainable practice of setting goals for each week and day, and reviewing your outcomes at the end of each week and day. And making course corrections if you find you're off track partway through the time period. At any given moment, you know what your current priorities are. And at the end of the time period, you have a clear idea of what you've accomplished, and anything you need to reschedule and tackle later.
I've tried apps made specifically for setting daily and weekly goals, but I've found less specialized and simpler is better. I've tried todo list apps like Todoist and an app called Sunsama that combines a todo list with a calendar. These are good apps, but I've found it best to maintain my agenda in a more flexible app like a notetaking tool. I'm currently using Roam Research to write out my agendas and track them. It's a notetaking tool in which everything is written in bullets instead of free-form.
An advantage of setting and tracking agendas in a flexible text-based tool is that it makes it easy to take notes as you work through your agenda. I find a technique called interstitial journaling really helpful. The idea is to briefly reflect throughout a work period on what you're trying to accomplish and how you're doing. If you have your agenda and your daily notes in the same tool, it's easy to jump back and forth between the two.
Ultimately, personal productivity systems are, well, personal, and vary from one person to another. But my big takeaway from my experiences is that simpler is better. The system should be just complex enough to enable you to set clear goals, track progress, and evaluate the ultimate results. And simple enough that you'll use it every day.