Severe regression in print quality after adding Z probe
Even with Auto Mesh Bed Leveling, you need to level the bed as good as you can. Your leveling grid show it varies between -0.403 and +0.145, that is about 0.55 mm or about 2-3 layers of filament (0.2 or 0.3 mm per layer). That can't be compensated for reasonably.


Re-level your bed so that the corners only have an absolute error of at max 0.1 mm around their average 0 - that's half what I consider the standard layer 1 height of 0.2 mm, regardless of other settings.
Make sure the 0 of the extended probe is a sliver under the nozzle, just to prevent piercing your bed on probing
G28 should bring the nozzle a hair sliver above the bed - if you move the head in X or Y direction (by hand after disabling the steppers, or move the carriage using the LCD) it should not make contact.