ipad backup to PC

Bought content from Apple can be downloaded again, if needed:

Redownload music - Apple Support

Redownload apps and games from Apple - Apple Support

Redownload TV shows and movies that you purchased - Apple Support

If you are using iCloud Photos, can download copies directly onto your PC:

Archive or make copies of the information you store in iCloud - Apple Support

Or use your iPhone to do so:

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

For copyright material purchased and downloaded from Apple, you will not be able to backup (or create other copies) to a Windows PC or other computer.

However, as these purchases are forever tied to the AppleID account from which they were purchased, should the need arise, you can download a replacement copy from Apple at a future date. Your purchases are actually a license to download and use content for as long as the material continues to be available; you don't "own" the rights to material.

As for material that you have "ripped" from optical media that you own, this is much the same. You can create a replacement copy for as long as you have access to the original media. If using a Windows PC (with iTunes installed) or Mac Computer (with iTunes or Finder - as appropriate for the installed version of macOS), you will likely have "ripped" the optical media to your Music Library - and from here synchronised your Apple devices with your Music Library that resides on your computer.

Redownload music - Apple Support

Redownload apps and games from Apple - Apple Support

Redownload TV shows and movies that you purchased - Apple Support

For your photos that reside in your iPad Photo Library, these may already have been synchronised with iCloud Photos - from where they can be downloaded to a new device, or restored to a device after a full reset. Photos that are not synchronised with iCloud can can be backed-up within an iCloud - or iTunes backup to your Windows PC or Mac computer:

How to back up your iPhone, iPad, and iPod touch - Apple Support

Other locally stored material on your iPad can be similarly included within your iCloud or iTunes backups:

Archive or make copies of the information you store in iCloud - Apple Support

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

Natively supported methods offer full system backup - consisting of data and device settings.

How to back up your iPhone, iPad, and iPod touch - Apple Support

In addition to native backup capabilities, it is possible to use a third-party App to backup data (but not device settings) to a variety of external storage options - including third-party Cloud services, external media devices and network storage. One App that comes readily to mind is FileBrowser Professional by Stratospherix:

https://apps.apple.com/gb/app/filebrowser-professional/id854618029

Stratospherix have an extensive online Manual and help files to with which to determine suitability for your needs.

https://www.stratospherix.com/products/filebrowserprofessional/filebrowser-professional-user-guide.php