We have recently increased to everybody the maximum number of blocks you can have in a record. The limit have been increased by 50%, from 400 to 600 blocks per record.
This upgrade has been applied as the new minimum to everyone, old and new users.
If you need more blocks for a special use case, please reach out at support@datocms.com
The limit seems high enough, but if you start building complex nested structures that are also translated you can quickly reach the limit. Unfortunately it's not a pricing issue but it's more of a technical limit as we need to run validations on all the new blocks that have been added. To avoid timeouts and long waits on the user's side we have added this limit, but if it's a blocker for you be in touch and we can test higher limits together.