This sounds like you weren’t using your upfront user research time well, because good user research, particularly for complex applications and websites, makes a huge difference. It’s a core way for UX designers to understand what users are trying to accomplish at a high level.
I’m not a huge fan of user personas or empathy maps, but high-quality user interviews are incredibly valuable. So is usability testing. So is card sorting and tree maps.
We do these things up front (and then again after we have prototypes). Let’s say you are redoing the user interface of a website. One of the best ways to figure out what works and doesn’t work is to usability test it.
Now, you might do foundational user work and be able to lean on that into the future and immediately get into prototyping a new feature or product, but you can’t escape doing this properly. You may have had the mix of user work wrong. I always advise to usability test early and often. You can even test paper prototypes and interactive wireframes.
This might be related to your consulting process, and maybe that needs tweaking to provide better value to your clients, but I lead a UX team at a SaaS company with several multi-million dollar products, and I assure you that good user research is worth millions to us.