have you tried to uninstall samsung notes and reinstall it from the galaxy store?
your notes should still be there once you log into your samsung account again
submit an error report if you can't figure out how to open samsung notes
Samsung Members app > + Button > Error report
I am sorry to hear of your recent inability to open Samsung Notes, and can see how this affects daily tasks even. In addition to the cache and data on the apps, uninstalling to reinstall, and rebooting the device, have you tried seeing if the issue persists in Safe Mode? It will help determine if the culprit is a third-party application. The guide for Safe Mode is here: https://www.samsung.com/us/support/answer/ANS00062983/
Also, you can try wiping your device's cache partition, which can help improve device behavior and stability. The steps are:
Performing a wipe cache partition removes any temporary files that may be causing an issue with the device. All personal files and settings are not affected by this option.
- Ensure the device is powered off.
If the device is unresponsive/frozen, press and hold the Power button (located on the upper-left edge) for approximately 10 seconds or until the device power cycles.
- Press and hold the Volume Up button (located on the upper-left edge) and the Home button (located at the bottom in the middle).
- While continuing to hold the Home and Volume Up buttons, press and hold the Power button (located on the right edge) until "RECOVERY BOOTING" appears in the upper left then release all buttons.
- Select wipe cache partition.
Utilize the Volume Up/Down buttons to highlight and the Power button to select.
- Select reboot system now.
Option is highlighted, utilize the Power button to select.
Please let me know if this helps.