This sounds more like a tech problem possibly related to your PS5
i've never heard of anyone else having issues with save corruption
you may want to contact sony tech support and let them know what is going on
of course they will tell you to contact the devs [which you have in this case] and are waiting to hear a response back
but ask if there is anything they can advise you to do to attempt to fix the problem
if this was on xbox i'd be able to give you a "fix" list that generally takes care of most issues
but playstation is outside my wheelhouse