There's GuidedTrack[1], which is a simple way to program complex surveys or tests, but can be used to create apps as well. It has been used to create Mind Ease[2] and UpLift[3].

There is a quick demo[4] on the site to show how it works.

Full disclosure: I'm a developer on GuidedTrack. Any feedback is appreciated.

[1]: https://guidedtrack.com/

[2]: https://mindease.io/

[3]: https://www.uplift.app/

[4]: https://www.guidedtrack.com/demo