Wifi keeps looking for networks after connecting, data rate slow

It's data rate (hold Option while clicking wifi) doesn't show anything unusual but 7mb (35 mb is "slow" btw it can go over 50 when not broken) Wireless Diagnostics (accessible from same menu) also shows no problem: but there is.

The BAD problem is it keeps dis-connecting and re-connecting every 3 seconds and every time it does it "messes up" browsing (or any other app un-suspecting hang-ups) and makes 7mb - about the speed of a 2,400 baud modem? (practically useless in 2020)

I did go into settings, delete the connection, re-create, and insure "it's 1st" in order. I checked system logs, wifi logs are horrendously long and no "OBVIOUS" problem is shown. (yea don't forget to make it 1st!!!)

my guess is that it shouldn't be continually searching for new networks after it's successfully connected - i believe it keeps on rebooting the connection every 3 seconds

i have another computer that never has a problem - so i'm "pretty sure" the problem is solely the mac OS software. it is "xfinity wifi" and i've had issues in the past with one pc being told it must sign in on web page while other devices (non-iMac) not asked to. but i've not seen that message in a year - and i haven't gotten any window hinting at login rejection of any kind for a year. also on this "service" there are no connection limits (i ran the modem software - no obvious problem there either).

The problem began when i began using Podcast (i paused radio, left it running days, during that the connection seized). I'm certainly not sure there's a relation. But i did restart and didn't load podcast so that's no longer a factor.

I do have access to the wifi phy unit: it hasn't moved in a year - it's ... "not the problem" - it hit ?50+mb easy in the past.

I've had this problem once before and deleting and re-creating the interface helped. But nothing I do works this time.

it's stuck in a loop and i have zero idea zero document to "deal with it" or why it is now a re-curring problem