Meanings of unwanted byproduct in English

Thorium reactors use an element that's already extracted in large quantities as an unwanted byproduct of other mining industries.

Importantly, the process worked without producing large amounts of methane, an unwanted byproduct of another catalytic process using large iron particles.

Soaring levels of expectation are Pochettino's curse; an unwanted byproduct, perhaps, of the job he has done since taking over in 2014.

Discomfort is something we tend to think of as an unwanted byproduct of bad design, but in this case, the discomfort is the point.