@JKoopmans I too use my iPad extensively so I have experimented with Things 3. I like it a lot.
But, there are four missing features that keep me in OF: 1) Lack of customizable perspectives, 2) Inability to nest folders more than one level deep, 3) You can’t complete a repeating task early, and 4) Lack of a Review feature like in OF. A Review feature is not necessary for doing a review but it makes it much easier with the ability to set review times based on project, e.g., some every week, some every month, etc.
Have you not found those to be important missing features in Things? Here is a screenshot of my OF perspectives: