I can't get past the file size limitation on icloud drive

You could use Winrar for Mac. Then you can chop the file into chunks of a user defined size. It is also more efficient to load up to cloud as an upload failure needs to redo a smaller file.

See this article https://support.apple.com/en-us/HT201104

What types of files can I store in iCloud Drive?

You can store any type of file in iCloud Drive, as long as it's 50GB or less in size and you don't exceed your iCloud storage limit. That means you can keep all of your work documents, school projects, presentations, and more up to date across all of your devices. Learn more about managing your iCloud storage.

You shouldn't store app folders, libraries, or .tmp files in iCloud Drive.

This is user to user forum and representatives are not here , you can post your suggestions at these links https://www.apple.com/feedback/icloud.html

https://www.apple.com/feedback/

Even if you manage to move the large fies to iCloud Drive, it will not be a backup, just an off-site storage. If you want to use iCloud Drive as a backup and not as a syncing service, you must never touch or use the files you are storing there, but solely work with local copies of the iCloud files.

But iCloud is meant to be used for syncing and updating your working copies between your devices, and then it is not a backup.