Check engine light and code P0430

I have a check engine light for P0430 which has something to do the catalytic converter. I've got one of those cheap obd2 Bluetooth adapters and downloaded the torque app to check out the voltage readings on the oxygen sensors. Both the upstream (B1S1/B2S1) are showing constant 0.1 and 0.8v oscillations, while one of the down steam sensor (B1S2) shows a constant 0.7/0.8v and the other downstream sensor (B2S2) shows similar oscillations to the upstream but at a slower rate. The problem I'm having a hard time figuring out is whether that one particular oxygen sensor is faulty or those readings are indeed accurate and somethings wrong elsewhere (maybe the catalytic convert?) That is causing that oscillating reading on the bank 2 sensor 2 downstream sensor. Extra notes; in my recent warrant of fitness, they have cleared the code and the check engine light came back on after roughly 50km of driving if that indicates anything. One symptom that I've noticed is loss of power? When I'm on the highway, going at a constant 80-100kph, sometimes (very rarely) within that range when I want to get up to 100, I have to push the pedal down a lot more to "wake up" the car and the rpm will suddenly jump to 3,000+ and will "regain" power. There seems to be no exhaust leaks though which someone else suggest me to test which has me thinking might be just the oxygen sensor is at fault.