Backing up 40,000 photos from iPad Pro 5th gen without Apple Cloud

You cannot burn a CD or DVD disk directly from an iPad. You would need to transfer the files to a computer with an appropriate drive and software. To copy your photos to a computer, see:

Transfer photos and videos from your iPhone or iPad to your Mac or PC - Apple Support

iCloud has nothing to do with your iPad not charging, so information has gotten scrambled somehow, either here in this thread or between you and Apple Support.

Regards.

Not having backed up your iPad is only a risk of losing your important data; it has nothing to do with whether or not your iPad will charge. Not being able to charge is a completely separate issue unless it's a hardware failure of the Lightning/USB port. Let's confirm what model of iPad you actually have. See:

Identify your iPad model - Apple Support

Post back with that information so we know what we're dealing with and we'll go from there. It sounds to me like the battery is failing, but whether that is premature or would be normal given the age of your iPad I can't say without knowing the exact model.

Regards.

Whoever you talked to either just didn't explain well (not all of any manufacturer's first-level support people are completely fluent in the language) or definitely should not be working as tech support for Apple, if it was indeed Apple Support you called. If it was some other support resource rather than Apple directly, then there's no way to know the qualifications of the people they have on staff.

It is possible that the iPad's battery is failing, not unheard of in a device that's up to three years old. If you haven't run through all of these steps:

If your iPad won't charge - Apple Support

you should do so and see where it gets you. If that still doesn't help, make an appointment at an Apple Store or authorized Apple service center to have your iPad evaluated.

Regards.