What are the Recommended fixes for DTC P0420 on 2009 Ford F-250 Super Duty

After fixing leak at the pipe and manifold (left bank) and replacing ALL O2 sensors that cat code came up. Any fixes other than replacing Cat?

1 answer
Probably not. IF emissions testing is done where you're at , you might seriously consider factory converter , as I've seen many aftermarket converters that aren't up to par with OEM converters. Just a thought.