You seem to have a misunderstanding of the law. The FDA is allowed to issue EUAs even when other treatments exist.
Under an EUA, FDA may allow the use of unapproved medical products, or unapproved uses of approved medical products in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions when certain statutory criteria have been met, including that there are no adequate, approved, and available alternatives.
Some of the monoclonal antibody treatments under EUA would be closer to being at risk.