Orbi RBR50 not secure website

There are several issues:

Yes, Netgear provides "90 days of complimentary support" with a new purchase. During that period, a customer may sign up (and pay for) extended support.  In over four years on the forum, I have seen exactly one person mention doing that.  The rest of us never even looked for the option.  That is why most people come to the forum (I certainly did).

The issue of "insecure" is related to the web browser.  In recent years, concerns about security have prompted changes in how web browsers operate. Ordinary (http) web connections are send in "plain text" and can be intercepted and read. Secure (https) web connections are encrypted using Secure Sockets Layer (SSL) which relies on digital certificates. Almost every web browser these days prefers a secure connection to any web site and complains if the connection is not.  There is usually an option (in tiny type) somewhere on that complaint message to say, "go there anyway".  After the first time, the web browser remembers and no longer complains.

The Orbi also has an https version of the web management. That version was 'secured' using registered certificates.  Netgear had registered a number of URL's (routerlogin.com, routerlogin.net, orbilogin.com, orbilogin.net, and a couple more) In August of 2019, the SSL certificates expired and were no renewed.  I have never seen an explanation for why the certificates were not renewed. (a) Somebody at Netgear forgot to do it? (b) The registration authority decided that it is absurd to have a certificate that says thousands of web sites all over the world are part of the company Netgear and refused to renew the certificate.  That fall, Netgear placed a "self-signed" SSL certifiate in the Orbi firmware.  (Anyone can create an SSL certificate. Microsoft Outlook has that option.) Unfortunately, web browsers also complain about self-signed certificates.  Just tell it to go on anyway.

At this point, you should be able to look at the Orbi Attached Devices page and at the Orbi log file to see what is happening with these two new computers.

There is a difference between (a) not being able to connect to the WiFi, get an IP address and access the internet, (b) getting "kicked off" either the WiFi or the Internet, and (c) specific internet games failing to work. More specific information will help diagnose the issue.

It will also be helpful to know the specific model of ISP device the Orbi is connected to.