Regarding_Notes_App Said:
"Notes App Cannot Open: [...]I can’t open it anymore and It’s probably due to the fact that the note that’s in there is so massive that my poor Iphone XR cannot load it.[...]"
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Clearing Internal Space:
If such is the case, then clearing internal space would seemingly fix this. Try clearing internal storage though use of the following:
What Space to Clear:
A. Clear Temporary Internet Files:
Clear your Temporary Internet Files(Cookies & Cache) of Safari:
Also...
B. Clean TV and Music Libraries:
Remove all unneeded files from your TV and Music Libraries. Full-Movies take up 2-4GB typically, and a bunch of those would take up a load of storage, ideally. So, if you have any movies that are not needed, then delete them.
Also..
C. Clear "Other":
Clear the storages named "Other". It basically contains unnecessary files such as caches that are used for system ease of use - all of which gather over time: How to Clear "Other" in your iPhone's Storage - Use Backup - User Tips. Caches would be being used for remembrance of application use. So, clearing other may be the way to go about this, as it would be performs through use of a computer.