Not sure about the "P6" code; hopefully someone can help with that. If not, you might trip the breaker to the stove for an extended period, then turn it back on and try again.

But find a magnet and check if your first set of pots is magnetic or not. If not, you probably needed the second set, but if a magnet sticks to the first pans, you didn't need a new set.

P6 lit up and steady is the highest power boost mode selection for a particular burner and it usually indicates there is a detected pan on it being heated. P6 flashing normally indicates no suitable pan is being detected or there is no pan at all on the burner.
Are you saying all four burners have a P6 flashing when a correctly sized pan is placed on each of their locations and selected on or do you mean when circuit breaker power is first applied to your range there is one P6 or more than one P6 flashing?

Here's quick little test:
Take a pot with a close to 4.5" bottom contact patch.
On your two left hand burner controls press ON, then press Lo, then press Hi enough times to reach 5.0. There should be two 5s flashing.
Take your pot and place it on a left hand burner. One 5 should be steady now and one 5 should flash. Move the pot to the other burner and the flashing and steady 5 should swap. Those burners are working correctly.
Shut off left burner controls and do the same test on the two right burner controls and right hand burners.
If there is no steady five anyplace your range might have got the pot detector circuit shook up in transit.
If the test works correctly, have fun!

Don't have any answers about why your induction stove isn't working, but you might want to check out this story and see if the CPSC has any info about your stove's issue.

Glass oven doors suddenly shattering
RI woman's Kenmore glass oven door exploded
22 Nov 2011

"Bonnie says her one-year-old Kenmore freestanding electric range from Sears was set at 350 degrees when the glass oven door suddenly exploded into thousands of tiny pieces.

If this has happened to your oven, the Consumer Product Safety Commission wants to hear from you immediately."

A link that might be useful:

ww.foxprovidence.com/dpps/news/local_news/glass-oven-doors-suddenly-shattering_3995829

'P6' is actually 'Pb' or PowerBoost.

Error codes start with an 'E'.

When you turn on the element, it displays '--'. If you hit '^', it goes to 'Pb'. If you first hit 'v', it goes to 'Lo'.

Due to power sharing, you cannot do 'Pb' on all 4 at the same time. Just one on one side and one on the other.

If yours is model 9991, check out page 15 of the manual, 'Setting Cooktop Controls'.