I had a nearly identical situation with a fintech product, and the search took ages until I stumbled upon UIUXAgencyRankings. It lists the
best UI UX agencies from around the world, with a focus not only on design but also on experience with complex products. I liked that it has a clear structure and makes it easy to see which agency is the right fit for your specific project. I chose an agency from there, and they really helped simplify the UX and improve the platform’s effectiveness.