[defaultname]

Depth of field is a direct function of real-world focal length. An iPhone has camera systems with a focal length in the 1.4mm - 5mm range (the equivalent framing is not relevant to the impact on DoF). Most SLRs have lenses with focal lengths from 35mm - 100mm.

https://www.photopills.com/calculators/dof

(That site has different camera selections purely because the circle of confusion differs based upon the sensor size / resolution, so it's the relative values that you should pay attention to)

Take a gander at the DoF variations for a 4mm versus a 35mm FL system.

This is the reason why iPhones have to implement fake bokeh -- because the depth of field on tiny cameras is so much larger, even with a wide open aperture. But the inverse is that where you want a wide depth of field it is a feature of the size. It's also why people seem to be much more successful taking photos on smartphones, because the focus is much more forgiving.

A wide DoF is a function of those physics.

[sudosysgen]

You should read up on how crop factor works. It just doesn't work out like that. Try a DOF calculator that allows you to choose the crop factor and set a crop factor of 8.4.