Ignoring the obnoxiousness of “just google it” replies, I would consider having to write a custom lambda function to enable global tables to be well within the realm of “CF doesn’t support it”.
Our experience also shows that custom resources can go into a 3 hour timeout cycle if you don’t handle error cases in your lambda perfectly, making them a sub-par development experience.
https://github.com/kspurrier/cfn-dynamodb-global-table/blob/...