GHL Sub accounts can be added after the first 300 by using the GHL Location ID of the account and adding it to a new sub account as a workaround.
You can find the location ID here
https://help.gohighlevel.com/support/solutions/articles/48001204848-how-do-i-find-my-client-s-location-id-
Go to the Sub account in GHL > Click on settings on the bottom left > Then click on Business Profile
You then add that location ID To the sub account that you just created
The location ID does not change and is static across all sub accounts.
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