I run my life pretty much entirely inside of Things (https://culturedcode.com/things/). It has just enough functionality that I can track and record things easily without getting bogged down in the meta-work; I've used it for five years without complaint or wandering eye.
Other notes:
- I follow GTD's philosophy pretty closely (next action, weekly review, that kind of thing.) The book is a little fluffy and some of the concepts are dated at this point, but worth perusing.
- Any state that has to be shared with someone other than me either goes to Apple Notes (friends and family) or Github (https://github.com/buttondown-email/roadmap/issues)
- No productivity system is going to solve all of your problems. It can make you execute better, but you are not One Perfect App away from the ideal version of yourself; when evaluating tools or systems, be sure to focus on very specific, concrete problems ("I am bad at following up with people after meetings", "I don't pace myself throughout the week", "It's hard for me to close out large projects") as opposed to nebulous ones ("I wish I had more time in the day", "I don't know which side project to work on")