IOS13 out, is SQLite gone?

I haven’t updated any of my devices to check as I don’t know how to revert.
Do you guys know?

Yes, SQLite is gone in iOS 13. Here is why and some workarounds:

https://blog.appstudio.dev/2019/07/the-future-of-sqlite/

It’s my understanding that the SQLite plugin will still work. Is that not correct?

Are there any programming samples available for IndexDB?

Yes, the SQLite plugin you mention will work. In the blog post, we recommend this one:

IndexDB programming samples are coming, but they are not ready yet.