https://bitcoincore.org is the official website for Bitcoin Core not for Bitcoin, as already posted earlier in this thread. And I'd follow the installation instructions there. Download Bitcoin Core only from official site and don't skip the next step to verify its authenticity, i.e. your downloaded file hash should match the published hash and the published hashes file should have correct signatures by multiple developers.

With an authentic download file you can then proceed with published installation instructions for your own architecture.