Beep boop, I’m a bot! I dug through the forum to get you started. I sometimes get things wrong though, so do with this what you will until a human has a look.
Google’s automated scanners decide this flag, not anything in the hosting itself, and the fix goes through Google. The knowledge base article below explains it. These warnings come from bots that look for phishing or malware patterns. The article says they sometimes flag safe sites by mistake, and that the exact reason can be hard to pin down.
The article’s recommended route is Search Console’s own review process, not just a Safe Browsing report:
Open the Security Issues section for your verified site and request a review there, once you’re confident nothing on the site could look deceptive. Google then checks the site manually and lifts the block if it’s clean. You’ve already sent a Safe Browsing report, so have you also requested a review in Search Console?
I also found a few other recent topics with the same “Deceptive pages, Sample URLs N/A” symptom. I can’t say yet that yours has the same cause, because none of them show a confirmed one.
The article lists “unsecured forms” and “vulnerable scripts” among the things that can trigger a flag. Your site has a login page and a join form, and your account is only a little over a week old. So it would help to know what the login page asks visitors for. Is it a login for your own site’s members only, or does it look like, or ask for, credentials for something else, such as a Google sign-in?