There is no way to increase/modify the integer value limitations on the Marketo side.
This is not a Marketo product limitation, it's the defined constraints of Integer data types.
If you're running into issues with values from a third party/webhook provider falling outside of the limitation range, this will present issues with the field value being accurately logged in Marketo.
In this scenario, it's worth checking with the third party/webhook provider to see if they have any flexibility around which field types they can allow (for example, String or Float type fields have less limitations and will allow for larger or smaller numbers outside of the -2147483647 to 2147483647 range).
For a full overview of Marketo field limitations, you can visit the below article:
Marketo Field Limits by Field Type