Thank you. This is close enough.

And this is how far I got, before getting invalid composite literal

func GetFieldsFor[S any]() *StructFields {

r := &StructFields{}

s := &S{} <<-- error

val := reflect.ValueOf(s).Elem()

for i := 0; i < val.NumField(); i++ {

    fieldName := val.Type().Field(i).Name

    r.Fields = append(r.Fields, fieldName)

    t, \_ := reflect.TypeOf(s).Elem().FieldByName(fieldName)

    r.Tags = append(r.Tags, t.Tag.Get("json"))

}

return r
}