I'd also want to integrate notes & TODO - but also time-tracking, i.e. the ability to "click" on any note/TODO and log time against it. Perhaps a TODO can be a note with a tag like "#todo"/"#todo-important"/etc, and time-logs can be child notes..
* project
** DONE investigation
...
** TODO implementation [2/3]
DEADLINE: <2021-06-21 Mon>
:LOGBOOK:
CLOCK: [2021-06-17 Thu 13:30]--[2021-06-17 Thu 16:03] => 2:33
CLOCK: [2021-06-17 Thu 10:30]--[2021-06-17 Thu 13:04] => 2:34
:END:
do X and Y, be careful about Z
- [X] part 1
- [X] part 2
- [ ] part 3
#+BEGIN: clocktable :scope subtree :maxlevel 2
#+CAPTION: Clock summary at [2021-06-17 Thu 16:06]
| Headline | Time | |
|--------------------------+--------+------|
| *Total time* | *7:40* | |
|--------------------------+--------+------|
| project | 7:40 | |
| \_ investigation | | 2:33 |
| \_ implementation [2/3] | | 5:07 |
#+END:
[1] https://www.gnu.org/software/emacs/manual/html_node/org/Clocking-Work-Time.html