I used things for a long time. Maybe my needs changed after iOS 13, but I switched back to Reminders. One of the reasons is things lack of support for dynamic text and the ability to make the fonts larger. So, I keep the simple stuff in Reminders, because it has a problem with sub-tasks — that interface just bothers me — and the more complex projects in things. It is annoying to have two of them, however.
The second one is Notes — I haven’t tried Notion, but I take a lot of notes using my Apple Pencil on my iPad. I do a lot of typing as well. I found that adding a hashtag makes it easy to search for things.