Manifold/header/muffler/tail Pipe problems of the 2010 Nissan Armada

In July 2017 and at 90k miles , my 2010 Nissan Armada began leaking exhaust fumes into the passenger cabin and the fuel economy dropped significantly. I took it to an authorized Nissan service station, which charged me $150 to diagnose a cracked catalytic converter exhaust manifold on both sides. The repair estimate was about $4,000 to replace the manifolds at the dealership. The manufacturer's warranty expired at 80k miles and I was told that this is a known problem with Armada and titan models. I shopped around for estimates and had the manifolds replaced by an independent mechanic with aftermarket parts for a total cost of $2,100 with a 2-year/24k miles warranty. In 2020 and at 125k miles (3 years/30k miles later), the same issue occurred and the shop would not extend the warranty. The Nissan dealership service department estimates the repair at $5,000, and the independent shop estimates $1,900. All of the mechanics (including the Nissan dealership) have advised me that they don't think the car is worth the investment at 130k miles considering the trade value is around $5k. I can't afford this repair twice in 3 years, and I'm driving my family around breathing in CO fumes that could harm or kill us. I primarily use the vehicle for day-to-day suburban driving with occasional camping trips - no hard or off-road use. Nissan should address this issue and reimburse the cost of repairs as this is a potentially fatal issue for drivers. I am now faced with a decision to invest almost half the value of my vehicle in a repair that may fail again, or to buy a new car I can't currently afford in the middle of a pandemic. Please hold the manufacturer accountable to its us customers.