Use the result of a shortcode as a variable

Hi,

I have a third-party plugin that imports data from external sources.
The plugin's shortcode works fine in Views for displaying data.

But I need to make some operations on the data and I'm having some difficulties.

When I do this:

{% set my_var %}
[my_shortcode]
{% endset %}

{{my_var}}

it will display the shortcode result as a number on the front-end, as expected.
However, in reality my_var is still equal to the text [my_shortcode], so I cannot do mathematical operations on it or save it to a custom field.

Is there a way to execute the shortcode first, and then have the shortcode's result as a variable (number)?
I have tried mb.do_shortcode('[my_shortcode]') but it doesn't seem to work...

Greetings,
Tom