[tryalrussel (OP)]

Please see the attached PDF. Here is one of the summaries provided therein:

Hypothesis:

Many drugs supposedly showing efficacy against SARS-CoV-2 may at least partially benefit from an overlooked mechanism of action. Namely, the drugs act as ACE2 inhibitors which, upon binding to the catalytic active site of ACE2, induce a substantial conformational change. This “protected conformation” is substantially less suitable for S protein binding (which takes place on the “outside” of ACE2 rather than inside the ACE2 catalytic active site cleft where inhibitors/substrates bind).

If this is true, then first of all, drug design/screening can target the(/one of the) actual MOA.
Furthermore, perhaps it is possible to treat COVID-19 with simple peptides which are suitable as substrates for ACE2. If used in great enough abundance, then these benign (and even nutritious) peptides would increase engagement of ACE2, thereby acting as quasi-inhibitors which induce the protected conformation. (It is of course necessary that the kinetics of the underlying processes be appropriate.)