I echo Rob!
I used to use Things, but felt it was trying to manage me rather than helping me - tasks appearing in Today and overwhelming me.
I’ve tried various workflows with Agenda, alongside other apps, and even a pen and paper notebook. I’ve currently settled on doing everything in Agenda, with occassional Reminders for deadlines.
The key to making this work, is regularly reviewing my notes and my diary - I try to do this at the end of every working day. I use On the Agenda for live notes, and I create a Today Note each day to jot down what I want to focus on today, often with links to the relevant Note where there are more details of the task(s).
I’m also now trying a ‘Week commencing x/x” note, dated from Mon to Sun. This is pinned. So when I go to Today folder, I see my priorities for the week, and also the specific things I’m going to work on today.
Might not suit everyone, but it’s working for me.