Easy way to check basic accuracy is to check the ambient temp and then compare it to the temp readings on the CTC.

I found them to be very accurate for the thermocouple on the hotend. Not sure what yours has, but mine uses K-Type thermocouples, so they are a known quantity. I did replace the thermister on the bed, as this was reading about 10C low.

TBH, people get quite hung up about the exact temp instead of seeing what works for them and then sticking with it. I use an indicated 230C for ABS and 210 for PLA and Ninja Flex.