If you feel emotion when writing an email (or Slack message), put it in draft and look at it tomorrow. I've never not edited or scrapped it the next day.
security@$COMPANY.DOMAIN inboxes are constantly inundated with BS security reports phishing for a payout. The situation has only gotten worse with LLMs.
Expecting a quick response is ridiculous. You should try taking on a role where it's your job to sift through all those emails .