Mine failed at 158,000km in 2017. I priced a Y tube from stealers, then for the same price had a set of
RIPP Long Tube Headers and catback exhaust with muffler shipped from the USA. (Exchange rate is worse now, so may or may not be viable, if available.)
Replacement cats from reputable exhaust shop would be the most cost effective way.
As humdingerslammer said, though,
check the sensors first. I ran some tests with a cheap bluetooth dongle in the OBD2 port & the Torque app, to watch the sensors cycling & see which ones weren't working properly, then swapped them left/right to see if the fault followed the sensors or stayed with the suspected bad cat. It stayed with the cat...