Are you logged in with Chrome? Are you running other Google products on your computer or behind the same router (e.g. an Android phone) that are logged in and have you added a payment method in Google with an address anywhere? Got any Google home assistant products around?

Otherwise they are probably using browser fingerprinting and cross referencing.

has anyone confirmed google does these? i personally haven't used google in years, dont hold a gmail account or use their services other than youtube which i do on a private firefox tab. while i do have a unique browser fingerprint according to https://coveryourtracks.eff.org

>Your browser fingerprint appears to be unique among the 327,358 tested in the past 45 days.

should i be concerned? now, if i use this same browser on any vpn, if youtube is doing fingerprinting then i am a unique user anyways so any ideas?

Create Firefox Profile: firefox -ProfileManager

Use Firefox Profile: firefox --no-remote -private -P profile-name

Create & Use Chrome Profile: chromium --incognito --user-data-dir=location/profile-name

On top of seperate browser profiles (at least in your VPN profiles), you need to do browser hardening and use something like uBlock/uMatrix to block everything by default. [1] I do not recommend using regular Google Chrome for VPN at all. Use something like Ungoogled-Chrome. [2] or similar security browser instead.

Also it is highly recommented if you use Linux/Unix OS, to properly firewall your VPN connection. So for example if your VPN connection suddenly stops working, it will not leak out any data. There is many tutorials on how to do this. I'm sure it is possible to do something similar on Windows too.

[1] firefox hardening; https://chrisx.xyz/blog/yet-another-firefox-hardening-guide/

[2] https://github.com/Eloston/ungoogled-chromium

[3] chrome hardening; https://peter.sh/experiments/chromium-command-line-switches/