Currently, that is a sample size of 1, Feliciano who went to the hospital briefly. However Dion Dawkins 1st Covid experience counts (not fully vax'd, hospitalized) as does Tommy Sweeney (pre-vax, got myocarditis, may or may not have been in the hospital). Those are the ones we know of, there could have been other players who visited the hospital and chose not to disclose it.
The vaccines have proven to reduce hospitalizations across millions of people. Using a sample size of NFL players is worthless data. So are individual anecdotes. By now everyone probably knows someone who was unvaccinated and had no serious symptoms, or maybe none at all. That has been possible from day 1 and no one disputes it.