Testimonials Slider using Flexbox and positioning relatively

Had some issues making the layout for this one. I decided to use position relative and z-index to allow the content overlap but this made making the breakpoints messier than i'd like. Layout started off well but when working with overlapping content i found it got hard to maintain cleanliness of code.

How would you have started the base layout of this project and handled the overlap of content?

I've also had an issue with making the image shrink along with the viewport. Had to set manual widths which isn't ideal. Is there a way to do that?

I'd happily take any advice or opinions on how i could have done this better :)