Essentially zero actual economists assert or believe that actual humans in actual economies are, or behave like, homo economicus. Essentially all are aware that it is a limited model, which attempts to approach certain important features of reality, but cannot always do so due to limits on information, comprehension, and subjective values. Meteorology is still a valid field of science even if its models are limited and incomplete. Likewise with economics.

"Economists think homo economicus is literally true" is a ludicrous strawman.