Markup frequently deletes PDF Annotations

Every time I open a PDF from the Files app, and add annotations using the Apple pencil, within about an hour, the display momentarily freezes, sends me back to the first page, and deletes all annotations. I've found a similar report from 2022 but it seems nothing has changed since then. My iPad is on iPadOS 17.7, and this makes it borderline unusable for the purpose for which I bought it. The iPad is brand-new, on vanilla settings, and with no customization whatsoever.

I like the native Files app, but I can't trust it with my work if I don't know if it will be randomly deleted. I don't know why this hasn't been addressed in a couple years, but it makes me seriously reconsider my purchase of an iPad. I would hope that any consumer knows what they're getting into before buying an iPad for marking up PDF's.