How do I export Notes in bulk using my iPad?

Perhaps the process outlined within this external article will help. The described process, using iPadOS multitasking, is remarkably easy - and exports one or more selected Notes to individual files within the native iPadOS Files App:

https://sixcolors.com/member/2021/01/export-your-apple-notes-in-bulk/#:~:text=Tap%20the%20Edit%20button%20to,Then%20release.

Once Notes have been exported (as .rtfd files), you can copy or move them as required to connected (or cloud) storage. You can open the .rtfd files with compatible Apps - such as Apple Pages.

You can easily select multiple Notes/files... although doing so in manageable batches is preferable to attempting to export/move thousands in one action. Try this method that works with most Apps:

Drag and drop between apps

With drag and drop, you can move text, photos and files from one app to another. For example, you can drag text from Safari into a note, an image from Photos into an email or a calendar event into a text message.

1. Use Split View or Slide Over to open the two apps you want to move information between.
2. Touch and hold a photo or file until it appears to lift off the screen slightly. To drag and drop text, select the text first, then touch and hold it. To select multiple photos or files, touch and hold one, drag it slightly, then continue to hold it while you tap additional items with another finger. A badge will indicate the number of selected items.
3. Drag the photo, file or text to the other app.

Use multitasking on your iPad - Apple Support