How to recover missing entries of Notes in iPhone disappeared after signing out Apple ID

Issue encountered: After signing out and back in my AppleID on my iPhone, only older note entries are present and all more recent ones had disappeared.

(1) iOS version: 17.2.1 (21C66)

(2) Notes in the iPhone had been always set to sync to iCloud.

(3) Before the issue occured, I only had 5G iCloud storage and had received notification regarding insufficient storage space.

(4) Before I signed out of my AppleID, I selected to keep a backup copy on the device.

(5) After I signed back in my AppleID and found entries are missing, I checked the Notes stored in iCloud.com. They are identical to what I have on the iPhone after signing back in. Also, my missing entries were present neither in the Recent Deleted folders in the iCloud or locally on my iPhone.

(6) I contacted Apple Support and was instructed to purchase iCloud+ and keep my iPhone powered up and connected to WiFi for at least 24 hours hoping that the missing entries would show up eventually. However, after 30 hours, the missing entries are still missing both locally and in the iCloud.com.

As the missing notes containing very important information. I would appreciate your kind advices on possible ways to get my missing entries back. Thanks in advance.