Very short *WAN* DHCP leases and Internet disconnection on every lease renewal

I've spoken with Comcast first-level phone support, second-level phone support, Advanced Technical Support, and Customer Security Assurance about the problem in the subject, all to no avail.  I'm hoping someone here can connect me with the group that can address the issue.

Similar problems have been reported in these forums before.  Some of the reports can be found via https://www.google.com/search?as_q=wan+dhcp+lease+only+2+hours&as_sitesearch=forums.xfinity.com

For more than a year, Comcast has been supplying WAN DHCP leases of two hours or less to my equipment.  While the short WAN DHCP leases would not be a problem by themselves, it is a problem that every time my equipment renews the WAN DHCP lease, the Comcast equipment drops my Internet connection for many seconds.

Because the short WAN DHCP leases require frequent renewals, my Internet gets disconnected more than 24 times a day.  Disconnections occur regularly during my business hours and "freeze" my SSH connections to remote hosts.

Here is a summary of the facts known and diagnosis done to date:

1. The WAN disconnect problem is not due to signal issues:
   
   The first thing Comcast first-level support did was send a technician to my house, who replaced a number of connectors and splitters at the premises.  As expected due to the nature of the problem, while the connector/splitter work did improve the signal quality (which was acceptable, if not outstanding, to begin with), it made *no* difference to the WAN disconnect issue.
   
   
2. The WAN disconnect problem is not caused by my router:
   
   I have removed the router from the network and reproduced the WAN disconnect problem with a computer connected directly to the cable modem.
   
   
3. The WAN disconnect problem is not caused by my cable modem:
   
   Comcast second-level technical support requested that I test with an Xfinity modem, which I am currently using in place of my cable modem.  The short WAN DHCP leases and the WAN disconnect problem are identical using the Xfinity hardware or my cable modem.
   
   
4. The WAN disconnect problem is not related to customer-premise equipment generally:
   
   The problem mysteriously "cured" itself for a time during December 2022, then reappeared in January 2023.  My hardware, firmware, and configuration remained the same during that entire time.  Obviously, hardware does not spontaneously "heal" and "re-injure" itself in this fashion, so the problem is not local to my premises.

Thank you