My Notes is showing 80 gb of storage I have deleted the app, restarted the phone but it hasnt changed phone says storage is full

I had a similar problem. Notes was taking 15G on my phone but only 9G on my iPad. This was choking my phone restricting updates etc. I deleted the app on my phone but only freed about 2G of space. I then reinstalled and deleted again each time I found I was getting a little more space. Finally when I had it down to under 1G (from 15) it asked me to connect it to iCloud again. I did this and after the notes eventually restored its now taking the same storage as it is on my iPad. I’m thinking it has worked. It’s like old cache files were maintained to speed up a restore.

1.

Try to free up iPhone device storage see this Apple articles below:

If you need more space for an update on your iPhone, iPad, or iPod touch

If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support

How to check the storage on your iPhone, iPad and iPod touch

How to check the storage on your iPhone, iPad and iPod touch – Apple Support (UK)

Clear Other storage on your iPhone or iPad

Clear Other storage on your iPhone or iPad - Apple Support

2. 

If you wish, you can upgrade the 5 GB free iCloud.

See -> What's the difference between device storage and iCloud storage?

What's the difference between device storage and iCloud storage? - Apple Support

See also the following Apple articles:

Upgrade to iCloud+ -> Upgrade to iCloud+ - Apple Support

iCloud+ plans and pricing -> iCloud+ plans and pricing - Apple Support

How to use iCloud on iPhone -> How to use iCloud on iPhone – Apple Support (UK)

Manage your iCloud storage -> Manage your iCloud storage - Apple Support

My notes app was taking 18 GB, but iCloud storage for notes showed only 250MB. I turned off iCloud storage for Notes and started the cycle "to delete and re-install Notes app" and each time it freed up 500MB

had a similar issue, notes on icloud couple of MB, on iPhone 14+GB. Offloading and reinstalling the app reduced the usage to a couple of 100MB again.