Turn off the Phone
Follow this word by word:
https://wiki.lineageos.org/devices/crownlte/install
* ensure that the device is on the latest Android 10 firmware * After installing Recovery, do NOT reboot to System or Recovery will be overwritten with Stock Recovery * if you want GApps, install the directly after Linage OS install: https://opengapps.org/?api=10&variant=nano * ..
Problems:
Get the latest Stock ROM from SamMobile (disable Adblocker to download!):
https://www.sammobile.com/samsung/galaxy-note9/firmware/SM-N960F/DTM/download/N960FXXS5DTE2/339392/
Follow instructions to install the ROM via ODIN (windows)
Extract the firmware file you just downloaded. You should get 5 files: AP (System &Recovery) BL (Bootloader) CP (Modem / Radio) CSC_*** (Country / Region / Operator) HOME_CSC_*** (Country / Region / Operator) Add each file to its respective field in Odin v3.14.4. Use CSC_*** if you want to do a clean flash or HOME_CSC_*** if you want to keep your apps and data. Reboot your phone in Download / Odin mode (make sure your device is off) with the following button combo: USB cable + VOLUME DOWN + BIXBY Once in download mode, connect your phone to the PC, preferably using the original USB cable you got with your phone. Odin should detect your device and a BLUE box will show up with the COM port number. (Be sure, the SAMSUNG-drivers are installed on your PC!) Do NOT tick any extra boxes. The only options to be ticked are F.Reset Time and Auto-Reboot. Click the start button, wait for Odin to say 'PASS' in a GREEN box. Once the flash is complete, your phone will reboot, and you can disconnect your phone from the PC.