The Regions article says the “Regions feature works only with newly added listings. So, if you have enabled this feature after adding a listing location, you need to update your listing”, however, I have over 50,000 existing listings.
How else can I create Regions without having to update every single listing?
There are several options here: you can either re-save the locations or create a custom script that will automatically do it, but it’s not possible to do this for so many listings at once, because the API quota will run out.
Yes, that’s right, it can’t be done in one go because the API quota will run out, so you will most likely need to write a script that will be configured for the API quota as well.