iPhone XR - No internet when connected to ANY WiFi - BUT other iPhone X,11 and even wired devices are OK

Hello - I am trying to troubleshoot an issue with my iPhone XR which is only 1 year old in April 2020.

My wife has an 11 and my kids have the X - they do not have this problem - when I am experiencing it. I am the only one with the issue which I started noticing last week.

Basically my XR connects to the WiFi APs - wherever I am in the home - but there will be no internet access - the WiFi connection DOES NOT say "No Internet" - it appears to connect as normal. But using apps that require internet connectivity just hang and don't work. Using OOkla speed test, Chrome, goole, ebay etc all show signs of trying to connect and get data but don't update or display content etc.

If I switch off WiFi and just use LTE all is back to normal.

The ONLY way to fix this - is I need to reboot my modem (provided b Spectrum) -once the modem is rebooted - my XR can connect to Wifi and be fine for a few days, weeks until it happens again. So far this is the 2nd time.

Please note the first time I noticed this, I rebooted my phone, I updated my OS, re-setted network settings, factory defaults etc - this did not do anything. ONLY rebooting my modem fixed the issue.

I thought there was some sort of parental controls or something blocking my internet - via MAC or IP - but none of that stuff is enabled.

Has anyone ever experienced this? Is my WiFi chip going?

Any help appreciated.

BTW - I found this post and am wondering if it has to do with the O/S:

https://thecellguide.com/apple-iphone-xr-has-no-internet-after-the-ios-13-update-heres-the-fix-7027

Thank You