This is why Dr. Yo and Dr. Yang both have stated that the appropriate time to use remdesivir is at the very early stages of infection. Once the disease progresses to serious, remdesivir will likely still work on the virus, but leronlimab is needed to fight the disease.
And since remdesivir has toxicity issues, why not just use leronlimab and keep remdesivir as a back up if the leronlimab enhanced immune system isn't able to fight off the virus alone.