Is pressing "Agree" when creating accounts or using applications, while not fully committing to their terms (such as alienating people from falsehood despite this contradicting the policies of some platforms), considered the conclusion of a covenant or promise, the violation of which constitutes a sin?

There is no objection to using applications that require agreement to terms containing Sharia violations, as long as the user intends to affirm only what is permissible and not what is forbidden. There is no sin upon him in that. The presence of obligatory forbidden advertisements does not prohibit creating an account, and the responsibility falls on those in charge of the website. The user must avert his gaze from them and refrain from listening to what is forbidden.