From the EU Information Provider's Guide[1]:

"Examples of cookies that generally do NOT require consent: ... Authentication cookies ..."

Also, even if you're correct in needing to have a cookie consent, you're still missing the decline option.

Finally, and I say this with all possible respect as a fellow entrepreneur who completely understands that you are pouring huge amounts of time and effort into this, your response was pretty inappropriate by being so emotionally charged. You sounded personally offended and reacted by lashing out and attacking the criticizer. As a startup, you're going to encounter that kind of criticism very often, so I'd suggest you find a different way of responding to it.

[1]: https://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm#s...