MicrosoftOutlook does look outdated, but it's also extremely powerful once you get into custom views and conditional formatting and custom fields. Unfortunately, none of this syncs to mobile.
I don't know what's available on Android, left that platform years ago and never looked back. I switched (again) to Goodtask for iOS. In Goodtask, steps (subtasks) actually sync with Outlook as plaintext. So if I have Step 1, Step 2, Step 3 (complete) in Goodnotes, in Outlook it syncs as this into the notes field:
[ ] Step 1
[ ] Step 2
[x] Step 3
And I can add subtasks (or mark them complete) in Outlook by just adding text with brackets. Which is very quick & simple. Another advantage is that I can now have long list of templated subtasks that can be easily copied into any task. Using automation script like Autohotkey, I can now populate the subtasks for a new task with a quick 3-letter command.
Goodtask also gives me other options I did not have with Todo, such as the ability to have some tasks set to recur after completion rather than after due date, Today widget on iPhone and iPad, a great Apple Watch app, location alerts, and a myriad ways to set up custom views.
