I'm researching mental health apps — would love to hear your honest experience (good or bad)

I'm a developer thinking about building a mental health app and before I write a single line of code I want to actually understand what people need. I also struggle with anxiety and depression myself, been in therapy for 2 years now, so this is something I genuinely care about , not just a business idea. I tried Calm and Headspace but honestly they felt overwhelming, too many videos, too much content, I never knew where to start. I quit both pretty fast. So I would like to ask you a few things:

1. Have you ever tried any mental health or wellness app? (I would like to know what apps)
2. What made you try it in the first place?
3. Did it actually help, even a little?
4. Did you quit using it? What was the moment you gave up?
   I would really apreciate every answear.
   I have in mind an application with an chat that will do CBT (cognitive behavioral therapy)