How to address P0430 P0420 and high fuel

Hello everyone,

I'm hoping for your input and opinion about this

CAR: Explorer 2013 V6 standard

Symptoms:
P0430 P0420 which is the catalytic converters are below efficiency threshold. Both sensors readings are about 0.74 constant when car is idling at full stop.
Higher than average fuel consumption for my driving conditions and style. Getting 15-16 mpg.
Car rarely feels like about to stall when come to a stop and it did a couple of times.
Other than that, the car is normal and there is no misfire in the engine

Things I did to help with the fuel consumption:
Used a fuel system cleaner from bg.
Changed engine air filter.
Changed spark plugs.

Form what I gathered searching and looking for possible causes are 2 possible issues for the codes and the higher than average fuel consumption:
1. A vacuum leak.
2. Fuel system pressure.

My questions are:
1. Will a vacuum leak trigger the CEL and specific code or not in my car?
If yes, it means that I don't have a vacuum leak and I should look somewhere else.
If no, is it possible that the vacuum leak could trigger P0430 and P0420 codes.

2. Let's assume I have a problem in the fuel system, higher or lower than normal pressure. Will that always trigger a code?


P.S: Watching YouTube videos and reading articles online trying to diagnose a car issue could make you go banana sometimes.



thanks

What are your short and long term fuel trims?

here is the values:
SHRTFT1=1.6
LONGFT1=3.9
SHRTFT2=2.3
LONGFT2=3.1

a follow up:
the downstream O2 sensores are not constantly reading 0.75 at idel. it read 0.85 after just starting the car after a long park. it's readings also jumping to very small values when revving the engine.

Probably bad cats. An infrared thermometer will help verify.

dose the fuel trim readings eliminate and possiblity for vacuum leak or fuel system issues?

should I look for exhaust leaks?

Pretty much.

Sure.