In truth, you are correct. I have no way of assessing the accuracy of Dr. Birx's remarks overall. Hence the comment "doesn't sound accurate" = which is a measured response that indicates some uncertainty - is intended to convey my opinion, based solely on my own experience and word of mouth from care providers. However, the statistics that I have seen suggest that the death rate from unconfirmed but suspected COVID-19 is likely to be small compared to the in-home death rate from untested individuals. It may be that my issue with accuracy lies in your interpretation of Dr. Birx's remark - no offense intended, just a disagreement. I believe that she was suggesting that other countries may be underreporting COVID-19 related mortality, rather than suggesting that we are overreporting it.
Of course, there's lies, damn lies, and statistics.
One thing we can all agree on is that this is a terrible situation to endure. Tough times, indeed