Learn Dutch: Kortom, de gebruiker kan deze bindende overeenkomst niet overdragen. - In short, the user cannot transfer this binding agreement.

No. Kortom (in short, briefly) acts as a linking word that stands outside the main clause, which is why it's followed by a comma. The sentence that follows it maintains regular Subject-Verb word order (de gebruiker kan) rather than inverting the verb and subject.

Why does bindende get an -e at the end?

Bindende is the present participle of the verb binden (to bind), used here as an adjective meaning "binding". When you use a present participle as an adjective, it follows normal adjective spelling rules. Because overeenkomst is a de-word, the adjective gets an -e ending.

Is overdragen a separable verb? Why isn't it separated here?

Yes, overdragen (to transfer / hand over) is separable (ik draag over). However, because this sentence uses the modal auxiliary verb kan, the main verb is pushed to the end of the sentence as a full, unseparated infinitive (overdragen).

Why is niet placed right at the end of the clause, just before overdragen?

In Dutch, when a specific direct object is involved (deze bindende overeenkomst), niet must come after that object. Because it is negating the action of transferring itself, niet is placed as far back as possible, sitting immediately before the verb at the end of the sentence.