No scanner after upgrade

This issue has been addressed hundreds of times on this blog. You should check the Cannon web site to see if a current driver is available for your unit. If you will bear with me, I will offer some things to be aware of. Whenever we install an operating system upgrade or some OS updates, printers and scanners will often stop working. Then new OS compliant software must be installed. Experience has shown that many printer/scanner manufacturers are very slow to provide updated drivers. Drivers for some older printers are never provided. (Apparently, they prefer to sell new printers.) What we can do is to thoroughly check the vendor's web site for updated software that works. If it is not available, then we should ask when it will be released. If that doesn't work, there are two alternatives. You should be able to scan using Apple's Image Capture app. It will scan but is not a full featured scanner app. You can download and try the app Vue Scan for free to see if it works and you like it. It is a full featured scanning app and does have a one time fee. I use it and can recommend it. I have no association with Vue Scan.

The last LiDE 600F drivers that I can find on either Canon USA or Canon EU sites are for OS X 10.8 and released in 2017. These would not be compatible with Catalina or Big Sur, and VueScan does not support this scanner unless one installs the drivers in a compatible operating system. Thus, as far as I can tell, you have a paper-weight that won't work with Apple's last two operating systems.

Never-the-less, I suggest contacting Canon and see what they can do to help you.