Just to make everyone aware that any Handwritten Entries in your Samsung Calendar are not backed up in your Samsung account. This has been confirmed by the Samsung Technical Department after I submitted an error report. Apparently the data entered is not part of your Samsung Account, so therefore this is not backed up. The only way to backup handwritten entries is to use smart switch.
This was discovered after I factory reset my phone once Android 13 One UI5 was installed. I don't agree with this and is very inconvenient as I lost valuable data.
I hope this information is useful to some people and avoids other people loosing valuable data,