After reading the article I get what it’s saying.. but isn’t any MRI _technically_ physics-based.

The term is "physics based model" it has somewhat specific meaning in context of mathemtical/physics modelling. It has nothing to do with all physics required to make MRI work. A model doesnt have to be based on physics to be usefull. You can often get some recognizable image by dumb stronger signal=> brighter pixel logic without fully modelling how why it changes. As long as change in material correlates with change in signal (doesn't even have to happen uniformly) you can get some picture and leave the interpretation to human. A simpler example would be temperature control. You can have simple hysteresis based approch of temperature under threshold turn on heater, above threshold turn off. Or you can have physics based model of what the heating power is, what's the heat capacity of chamber, what's the heat capacity of object, how the temperature diffuses within object, what's the thermal resistance of interfaces between heater, target and temperature sensor. Many everyday systems systems are controlled by generic PID controllers without physically modelling how exactly the process reacts to input, PID can be be considered a mathematical control model with sufficient parameterization to approximate various physical systems. You could also make an AI based model and create a signal processing function that way. For many drones PID coefficients are tuned by hand, it was quite a surprise when one of controller manufacurers had made a physics based model to calculate suitable defaults based on drone mass, momment of inertia and maximum thrust.

Technically the tittle isn't lying. Researchers created new physics based model which is more detailed and makes less simplifications compared to old physics based model. The qualification also clarifies that potentially sharper image won't be achieved by new device model or a picture of 3d model printed on marketing materials.

Does seem like advertising “rack and pinion” steering on a car…