Assuming the plugin uses standard WordPress users, you could try this in your template:

<?php $current_user = wp_get_current_user(); ?>
<a href="https://www.mywebsite.com/user/<?php echo $current_user->ID; ?>">Link to page with user URL</a>

Thanks for your answer!
Sorry, I didn’t had any email notification of your reply.

<?php $current_user = wp_get_current_user(); ?>
<a href="https://www.mywebsite.com/user/<?php echo $current_user->ID; ?>">Link to page with user URL</a>

Hum… doesn’t work.
If I copy/paste the code in a post in the Classic Editor > Text tab and Publish, nothing is displayed :-/