Car Advice - Catalytic Converter on Honda

Figured I would get some car advice from members on the forum. Sadly there isn't any type of car forum so I decided to post it here.

I have a 2.4 liter 4 cylinder 190 hp 2011 Accord EX-L. I'm the original owner and the vehicle has 158,000. Vehicle has been spectacular up to this point, never any major issues besides the occasional battery going dead.

Always on top of oil changes and fluid changes. Coolant was changed at 100,000 miles as recommended. Valves were adjusted last year with a new valve cover gasket. Serpentine belt was replaced 2 years ago. Essentially I've always been on top of getting maintenance done.

I noticed on Friday that my engine performance seemed down (I know my car very well and could just feel that something wasn't right). Last night while driving my check engine light comes on for the first time ever.

I go to Advance Auto Parts today and they pull the code. P0420 was the code. After looking it up it indicates an issue with the Catalytic Converter. I'm guessing the Catalytic Converter has gone bad and will need to be replaced.

Of course we all know this is a bad repair. Probably looking at $1500-$2000 and after a medical issue late last year causing me to miss a few weeks of work I honestly don't have that type of money to spend.

So I wanted to ask you all this, lets assume for this scenario I don't care about polluting the environment (I do but maybe not at $2000). My state doesn't do emissions testing so I don't have to worry about it failing that. Besides the environmental issues would this cause me to destroy my engine? Again I will say I notice decreased engine performance and not as much responsiveness in acceleration (both tell tale signs of the converter) but it still drives smooth. Is there a reason to replace it soon besides environmental reasons? Will a bad converter eventually hurt my engine and cause even more expensive repairs?