The presumption of detention is rebuttable, but very daunting. A person charged with a presumption case offense must rebut the presumption by clear and convincing evidence. This is the second most onerous burden in our law, right below proof beyond a reasonable doubt. Release is obviously far less common in these cases, but people with minor (or unprovable or nonexistent) roles in the offense with minimal criminal history who have a third party custodian stand a chance, and should not simply waive the detention hearing. In fact, the only time a person should waive their detention hearing is when they are being held outside the Federal courts: i.e., they would not be getting double credit for the holds if released, or people who have immigration holds. Even in these cases, the court can reopen the detention hearing if circumstances materially change, such as making bond on state charges (common) or getting the immigration hold lifted (rare).
Detention hearings are great opportunities not only for release but for discovery. The government begins with the burden in every case, so their agent must testify. Your attorney can cross examine the agent on key facts and circumstances of the case. You can dig for critical pieces of evidence relevant to the hearing, since the weight of the evidence is a factor the judge must consider. For this reason alone, a waiver should be avoided if no outside holds exist.
If the court denies release and orders detention pending trial, a person has the right to appeal the decision to the Article 3 federal judge. The presiding judge hears the case de novo, which means they make their own ruling on the evidence. The percentages of detentions getting reversed by the District Court is very low, and the subsequent successful appeal to the Fifth Circuit is virtually nonexistent, so it is very important to hire a lawyer who knows how to most effectively present your case for release in the magistrate court.