Hello @MihaiHM ,
The theme does not have the option to extend the left area width. It requires code customization and as much as we would love to help you with this, we are unable to do as it falls beyond the support we offer for our product.
For this, our suggestion to you is get the Pro version, where you can achieve this task by easily disable/enable theme options.
To buy the pro version, follow below-given link:
https://keonthemes.com/downloads/bizplan-pro/
Or hire a professional developer so that your theme is not affected in any way.
To hire a developer, follow below-given link:
https://keonthemes.com/hire-now/
Best Regards!!