I would like to build a very niche expert platform for the Spain & Latin market and am trying to see what theme would allow for voice but also text questions to be asked, all pre-paid. Many thanks in advance.
This is an old question that needs a refresher for 2023.
You can build pretty much ANYTHING on WordPress and the theme is just the look of the website even though it MIGHT determine how some functionality is going to be developed.
It sounds like there is going to be some digging to find plugins that provide the functionality you are looking for OR they need to be custom-developed: either way WordPress offers what you seek.
In 2023 we have several theming platforms available for WordPress. LONG gone are the days of getting a theme and only sticking to what it offered! I have tried more than a few over the years and the BEST is Elementor: https://elementor.com/.
If you are reading this answer in 2023 and are interested in exploring what to do to get your new brand or company started, give me a call to help you see what options you have!