Inconsistency on my wifi as of the last 2-3 weeks or so

My wifi has been inconsistent as of late.  I usually get 1g to my laptop.  As of late, it will appear to lose throughput.  I've seen it drop to 10mb.  As a result, I can't connect to web pages, hold zoom or Amazon Chime calls.  Outlook disconnects.  Slack does at times too.  So, I would love to blame it on my recent laptop upgrade to Windows 11, but running ookla Speed Tests from my iPhone (from the same 6 feet from the router) shows similar performance issues.  This morning, using the automated chat feature, Xfinity said "your connections are not normal, let's reboot your router".  things worked okay for a couple hours.  Other times, when it runs it check -- sometimes I struggle getting to the chat page - so when it runs, then it comes back fine... and at the same time, my phone seems fine again.  So, multiple wifi devices, different OSes (Win10, Win11, iOS) ... different times of the day...  router might be 6(?) months old.  They replaced  it - but I've had the high bandwidth to the house since 2010.  All of sudden I'm now having problems.  

Thoughts/Comments?