Back with an update, after waiting a few days for the environment to warm up, and the humidity down to 9%, filament hopefully dried, a freshly cleaned plate and everything on default for PETG. Chamber temp was around 30º (Celsius)
And this is what I’m greeted with., A failed calibration test.
Compared to what it was once printing, which I thought was fantastic.
And Support, on my support ticket is completely missing in action. So I’m placing this here for the record, so that others can see the “out of the box” experience I’m having with this new printer.
Update, an hour later: So turned the plate over, and tried again. Success! So I have no idea what the difference is between the two sides, as it being a completely clean plate.
Even the back of the print of the calibration test is better, compared to parts printed earlier in the day? As you can clearly see line graininess of that left part, compared to the one on the right.
Update: Using the High Quality setting, Found an older calibration HQ preset, and since replacing that with the new Calibration, after getting it to work, it seems that we maybe back in business. As the new print, I had difficulty getting it off the plate! Which I think is a good sign.
New part on the left. On the right, the old part was terribly rough to the touch. (Come to find out, that’s what the Ironing setting was creating. I thought ironing was meant to smooth the part, not make it worse?)
Update: Tried another colour, Bambu PETG Grey, using the same High Quality setting and new calibration preset. Worked also. It also seems to have resolved my BRIM, part bowing issue, where parts were beginning to bend off the plate. New on the left, old on the right. 
And boy, these new prints are alot more difficult to remove from the plate.
Update: Back to the Standard setting. Very little raising of the print off the bed. And removing them from the plate is alot more difficult.
Things are looking good!
Update: So I turned the plate back over, using the Standard setting to see if the initial failure of the calibration test was related to the plate (dirty).
Nope, a completely successful print. And now everything seems to be like new!!!
Conclusion: I believe changes in the app update conflicted with something in the filament presets, and seems to confirm what @no8080 found during his testing. And thus had nothing to do with a dirty plate.
Proposed fix, when updating the app, delete any presets and rerun the flow rate calibration.
Hope this helps someone, and saves them the frustration I have gone through for the past week.