@dang can we please update this title to actually reflect the source title: "Controversial paper claims satellite 'megaconstellations' like SpaceX's could weaken Earth's magnetic field and cause 'atmospheric stripping.' Should we be worried?"

Generally, no this isnt possible. The planet's magnetic field is generated naturally by the movement of so much hot iron and other elements it eclipses the total of most of the other freely available metals in the solar system.

The Earth isn't the biggest planet, but we have the biggest single conglomeration of metals outside of the gas giants. Combine Luna, Mars, and all of the known asteroids and it only almost comes to a similar mass.

A few dozen tons of launched material isn't going to have any noticeable impact on our magnetic field.