Navigation tablet / mobile app left side

I have the task of creating an application for the elderly (users). I work in a medical technology company, so my users are often very sick.

The application will be distributed on our own tablets and the use of smartphones will be limited.

This is the blocking of the application. Red is happy. The navigation is at the bottom. The top bar is above the white line at the top. As you can see, the green color on the sides is a free / unused space.enter the description of the image here

Because I wanted to use the free space to get a little bigger content (fonts and larger icons), I wanted to eliminate the free space / green space.

For this I moved the navigation from the bottom to the left. Like that.

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This has allowed me to increase the size of the content.

My question is: do you have any experiences with left-hand tablet navigation in terms of UX. Is it something that can work or should I avoid it? What are your thoughts guys?