my two tracerts, with vpn and without, end with exactly the same set of lines, yet the website is still inaccessible from a Russian IP.
when browsing without a vpn, my browser tells me that the connection isn't secure and there is no SSL certificate. however, a vpn with european ip gets access without issues in the same browser and loads the certificate.
i asked someone else to try, and they said that their normal ip had no access, however using a vpn which connects to an ip within russia they were able to load the website. not sure what's going on there, i asked them to also check what certificate they get on the vpn, still waiting for the response.
upd: just heard back from the other person. they use Kaspersky Antivirus which somehow installs its own ssl certificates, so that's why the website could be opened from Russia.
ps. i do not recommend installing Kaspersky to fix the issue.