I've always used ColorNote. It does have several advanced features but they're all optional. It's been updated for 5 years now and basically hasn't changed. Still free, no ads, easy to use. A rare exception on the Play Store. Whole app only 4Mb.

Do owners actually want thin? I've never heard anyone brag about how thin their phone is. I'm almost positive the thin fetish only exists so companies have a nice easy number to advertise, like all the useless numbers they slap on processors and TVs.

Wouldn't matter to GDPR, people have sued over much less, right to be forgotten is a thing, and you don't need a lawyer to do it. Could be worth everyone sending in a request to inundate them and they'll have to sift through them to follow the law correctly. Once received, any valid and legal request must be actioned within 60 days, and most companies take 15-30 just figuring out how to do so. We don't have to flood their legal department much to make them lose track of something, and if any of you are EU citizens, your request must be honored.