Garmin Connect (app and web) does not report (display) VO2 over time intervals (4, 12 wks, 6/12 mnths) and displays the FTP merely as a constant line across the same intervals – any suggestion?

As for the VO₂max - I see only a single value in your stats, so that's the reason why there is no line. There is some basic troubleshooting information available in the article My Recorded Activity Did Not Update the VO2 Max Estimate | Garmin Customer Support. Make sure to pay attention to the last paragraph too, even if you know you never associated the device with another Garmin Connect account. Also please note, that fixing the association will not fix past data. It will only help for future rides.

As for the FTP - it there is a problem with the device/account association, it could be the culprit too. If not, again some tips are available online at What Is the Functional Threshold Power Feature on My Garmin Device? | Garmin Customer Support

If nothing helps, and nobody else peeks in with other tips, contact the Support, and then please update this thread with the outcome - it may be valuable for other users searching the topic in future.