Can I update the maximum amount of custom fields?

Unfortunately, the maximum value for a custom field cannot be updated because it is a global hard coded setting. However, you can use a JSON object instead to achieve the desired functionality. JSON is limited to 1MB per member which can hold a good amount of data. 

Steps to follow:

1. Access the helpful information provided here.
2. Follow the instructions in the documentation to learn how to use JSON for your custom field requirements.