Is it WKT geometry? Try sf::st_as_sfc on the column itself. Then you can use st_as_sf on the data frame as a whole, and you can control which column gets used, what its name is and so on. This is a little fraught since this text-only geometry won't come with a CRS, so there's a little more required to pass that metadata into sf itself. That's why neither of sf or DBI will ever be able to make this completely seamless, there's too many options - but the tools are there and are atomic enough to be able to piece things together.
Also, a spatial DB will be able to cast geometries to many forms, so there's lots of ways this can be handled if one particular way doesn't work. I don't see enough information in your posts though to be able to provide good answers. Can you at least give a table summary, a sample of the geometry column, etc.