Check engine light is on with codes P0420, P0440, P0441 and P0441

P0420 is the code for a converter that isn't operating correctly. It is tripped when the sensor after the converter sees that the converter isn't working up to specifications. While it could be the sensor it's not as likely as it being the converter itself. However the other codes are for EVAP leaks and those could cause the converter to be poisoned with extra fuel and cause it to fail. The P0440 is a large leak, the P0441 is for incorrect purge flow. The common cause for the second code is a stuck open purge control solenoid, and if it's stuck open it can also cause the P0440 as it would appear as a large leak. The valve sticking open allows the fuel tank to vent directly into the engine. That will cause it to run rich because it cannot control that extra fuel. This would also cause a rich mix to go to the converter and they really don't like that. I would probably repair that first, then erase the codes and then look at what the O2 sensors are actually reading once the leak is repaired. It's possible that the extra fuel is causing the P0420 code but not as likely as a bad converter
The solenoid is mounted on the side of the air cleaner housing and looks like the image. Testing is easy to do. Disconnect the power connector and the hoses and remove the valve. Then just try to blow through it in both directions. It shouldn't let air through either way. If it does it's stuck open and needs to be replaced.

The leak would be an internal vacuum leak. That solenoid runs from the vapor recovery canister up to the intake. It's job is to pull fuel vapor out of the canister in controlled amounts at specific times. When the EVAP system operates normally it captures the fuel vapors and stores them, then that solenoid is operated under computer control to allow the engine to burn off those extra vapors. The EVAP system runs tests on itself and in this case has discovered a leak. However the leak isn't something you can see. What happens in the test is that a valve on the fuel system closes off the vent system, then the computer counts how long it takes for the system to build a vacuum in the system, once it hits the correct level the vents are opened and it times how long it take for the vacuum to drop. If any of the valves fail to close and it cannot pull a vacuum, it sets the P0440 code or if it stops the test and the vacuum drops suddenly, it sets the same code. In this case with a leak and incorrect purge flow I would look at the pieces of the purge system that could cause a "leak" but not set other EVAP codes.
I would fix the EVAP first, then go from there, it's cheaper and if the converter is bad, you are not going to make it worse. However putting a new converter on while having an internal EVAP issue could reduce it's lifespan rapidly.