"When Good Intentions Go Bad — False Positive Microplastic Detection Caused by Disposable Gloves" - https://pubs.acs.org/doi/10.1021/acs.est.0c03742

From the study in the OP you cannot derive that current studies on microplastics are not valid. The headline framing that scientists have been measuring their own gloves, is science journalism doing what it does best...

Stearates are water soluble soaps, so any study using standard wet chemistry extraction, and that is most of them, washes them away before analysis even begins. Stearates also cant mimic polystyrene, PET, PVC, nylon, or any of the dozens of other polymers routinely found in environmental and human tissue samples.

Nothing to see here.