I started ordering polymaker coming from overture. Both brands had swapped to cardboard spools. But as mentioned polymaker has a file uploaded to printables to print a ring border so they can roll easier. Especially since the cardboard rolls can get dented if shipped haphazardly.

https://www.printables.com/model/495778-polymaker-cardboard-spool-adapter

But I've gotten lucky, and the spools I have received with cardboard haven't been damaged. But I have considered printing a few of these just in case...