As someone who has taken their child to consult with an occupational therapist, I have to disagree with your distinction between OTs and RDs. From our experience, the OT was much more focused on creating a tailored meal plan for our child's individual needs, using strategies like mixing new foods with familiar ones. The RD seemed more concerned with general nutritional guidance.
In fact, it was the OT who suggested trying different presentation styles and smells before introducing new tastes to help our child become comfortable with new sensations. We also found that letting our child take ownership of food choices at the grocery store was a great way to give them agency and control over their experience, but it's interesting that you mention it as if it's a new idea.
It's worth noting that every child is unique, and what works for one may not work for another. In our case, introducing new foods in small ways, along with the sniffing time concept, has been incredibly helpful. However, I am curious - do you find that OTs and RDs often have limited perspectives, or are they trained to be adaptable and take into account individual differences?