Emissions Issues with P0430

[D-Angler]

I have had codes for P0420 and P0430 on my 2017 Expedition. Did all the recommended things, cleaned the MAF, checked for air intake leaks and exhaust leaks, replaced O2 sensors and eventually replaced the cats because the rear O2 sensor was fluctuating a lot and everything else had already been done. Still having the code and I am at a loss now. Any help would be greatly appreciated.

I do have a negative long term fuel trim on one back, just over 10% and the spark plugs were changed earlier this year.

Thanks