Kindly refer to the following links:
How do you make Wudu if your nose is stuffed. Or if one of your nostril’s is stuffed? (website)
Should we gargle water in mouth when making wudu? How far to sniff up water in nose
How to do wudu when you have stuffed nose?
Nose is blocked most of the time, how to do this in Wudu?
How to rinse your Mouth and Nose while making Wudu & Ghusl
Get the water up to the best of your ability.