ME/CFS is an under-researched, multi-system disease that affects people in a multitude of ways and is very hard to diagnose. There are no accepted bio-markers yet. There are, however, many well-respected researchers in the field, and more are beginning to enter it from all kinds of disciplines. Basically none of them think this is a psychosomatic illness. This is a good place to start for getting an overview of interesting current research: https://www.omf.ngo/the-end-mecfs-project-2/
Wouldn't the researchers entering this field be selected for thinking this? Their opinion seems less useful than, e.g., a position statement by an encompassing field.
"Position statement" = collective statement by a group of experts on a topic. "Encompassing field" = group of medical experts who study a larger body of knowledge that includes CFS/ME as a subset.
Like, in physics there is a big field of people who study dark matter, with subfields who specializes in certain (often mutually exclusive) hypotheses about what dark matter is made of, e.g., WIMPs, axions, etc. If I wanted to know whether a new hypothesis about dark matter was plausible, I'd want to hear what all the dark matter specialists thought, not just people who already committed to studying that particular hypothesis.