If you've come across intranetaya-my.sharepoint.com, you're likely looking at a corporate SharePoint site used for internal documents and collaboration. That's exactly what this is. The domain is a subdomain of sharepoint.com, meaning Microsoft hosts and manages it. Unlike a standalone website you'd find in a search, this one exists solely to let employees of a particular organization sign in via Microsoft's login page.
For a private intranet, the signals here are as expected. Security is strong with valid encryption and no malware issues. The site doesn't have a public web presence because it's not supposed to have one. There's no Trustpilot or Wayback history, but that's normal for a login portal that isn't meant to be crawled or reviewed.
If you're an employee or authorized user, you can safely use this site. If you're a customer or outsider researching the company, you won't find public reviews here, but the fact that it's a Microsoft service adds a layer of trust. There's nothing here to suggest it's a scam or fake.