There are kaios phones, which are basically very weak smartphones (like 512 mb of ram weak) that run kaios, which is android. They perform poorly enough that you wouldn't want to use for social media, and you can run whatsapp on them
KaiOS is more like "Firefox OS" than Android, but otherwise, yes.
I did a 30 day dumbphone challenge a few months ago. Was originally going to use a Nokia with KaiOS but wanted to be able to re-purpose it afterward so I went with an Android-powered flip phone.