I believe that Jellyfin, Immish, and NextCloud login pages are automatically flagged as dangerous by Google. What's more, I suspect that Google is somehow collecting data from its browser - Chrome.

Google flagged my domain as dangerous once. I do host Jellyfin, Immish, and NextCloud. I run an IP whitelist on the router. All packets from IPs that are not whitelisted are dropped. There are no links to my domain on the internet. At any time, there are 2-3 IPs belonging to me and my family that can load the website. I never whitelisted Google IPs.

How on earth did Google manage to determine that my domain is dangerous?