Word to describe writing that only contains superficial knowledge and no genuine substance

Solution 1:

facile: (especially of a theory or argument) appearing neat and comprehensive only by ignoring the true complexities of an issue; superficial.

Source: https://dictionary.cambridge.org/dictionary/english/facile

Solution 2:

The word I'd choose here (this after OP's edit) is specious.

specious adjective 1 Superficially plausible, but actually wrong.

a specious argument ...

This argument was presumably specious since the integrated system has since been jettisoned in favor of subcontracting. ...

Hucksters flaunted their specious cure-ails on posters, broadsides, and other printed formats.

1.1 Misleading in appearance, especially misleadingly attractive

(ODO = Lexico)