It’s a native dialogue we have no control over. We call it when you press the button, then what’s shown (or not…) there, is up to the OS. Sadly this bug is in the OS since iOS 13, it seems like it’s not going to be 17 that fixes it.
Personally, I don’t use that option anymore, for other devices, Sync does the job, if I need to export it anyway, I save to Files and either share from there (if it’s not broken too…), or put it in a folder that’s synced with other cloud providers.