2018.cx-9 rough engine after oil change
 

I am at a loss as to what to do next. I have a 2018 cx9, with 70k kms on it. Took it for regular oil change at the dealer, got the car back, noticed very rough drive. On a hunch checked the dip stick, oil was over filled by quite a bit. Took the car back, they apologized, drained the oil, got the car back, much better, BUT STILL NOT AS Smooth AS BEFORE THE OIL CHANGE.

Numerous visits back and forth, dealer thinks it's fine, can't do anything else, says they checked everything. On my own I got the spark plugs changed, still no difference. Car simply doesn't feel as smooth or collected as before. Engine seem noisier, fuel economy seems a little worse. I really don't know what to do next, any tips would be appreciated.
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