OnePlus Nord CE6 is downgrade compared to CE5.
OnePlus Nord CE5 launched for starting 24,999 and CE 6 launched for around 27k.
CE 5 has Super Fluid Amoled Display vs CE 6's LCD display.
Since the CE 5 has Amoled, it can turn off its pixels in dark mode and save much more battery than CE 6, so the 8000 mAh battery is a marketing thing.
The main camera lost the Sony Sensor.
*I haven't tested the front camera so anyone can tell which is better or worse.
The Ram is downgraded from LPDDR5X to LPDDR4X.
The software updates have been decreased from 4 years to 2 years.
A larger vapour chamber (7041mm²) in CE5.
Mediatek Dimensity 8350 Apex in Oneplus nord CE5 is significantly better than Snapdragon 7s Gen 4 in oneplus nord CE 6.
OnePlus Nord CE5 still supports MicroSD card upto 1TB while CE6 has no slot.
CE5 has ultrawide but CE 6 only has macro.
Now for the small upgrades of CE 6:
Haptics are improved,
Water resistance from IP65 to IP69K.
CE 5 has mono speaker while CE6 has stereo speaker.