Frequent internet disconnects

All devices simultaneously.  All are wireless.  When this happens, I see my WIFI signal at 5 bars with the report connected, no internet.  If I wait it out, the service returns.  Reboot of the modem, router, and extender have no impacts.  Another symptom is I only see my WIFI as a choice to select from.  When there is service I can see several other signals in my neighborhood.

I will read your fixes when I get home, but I have given up on your CHAT so called help line.

Ok....reviewed the articles.  There has been no change in my router / extender location in over 3 years.  The disconnects started about 3 months ago.  We can rule out location, frequencies, etc, because I located and tuned to best performance.  The oldest piece of equipment is the COX supplied modem.  The next is a 3 year old modem.

Bypassing the router increases speed, but limits any other device from accessing the internet, so I don’t see that as being a valid option.  I can do a direct wire to the router, which will check the WIFI.  The connection will be modem - router - laptop via CAT5.  Connections will be 24 inch runs.  I will have all other devices via WIFI.  

The problems with dropping are during hours when the neighborhood are streaming as many of them have cut cable but are using COX internet.  We have no choice until Verizon runs fiber.

Does this mock-up meet your needs to eliminate issues on my end?

Setup complete.  Hardwire to modem 90 MBPS.  Hardwire through the router 25 MBPS.  Wireless 16 MBPS.  All tests done with the same computer.  Computer in all cases in the exact same location.  Note.  Other devices were on line during all tests except the hardwire to the modem.

I made a change, because the router seemed too slow on hardwire.  I did a factory reset and a reconfigure.  Hardwire through the router is up to 90 MBPS.  Wireless in close proximity to the modem is 33 MBTS.  Far side of the house through the extender is 18 MBTS.

Believe the COX modem is fine.  Router might need an upgrade, but still fine for my applications.  I will monitor connectivity, but this forum was helpful.  You chat help line...not so much.  Please leave this open for a few days.  If I make it through the upcoming weekend, we can put the blame on my personal router and confirm there were no issues with COX service or COX equipment.