Hello!  

I had the warning on a site with 2 time UK gallery:

Warning: Cannot declare class TextCompat, because the name is already in use in mod_uk_gallery/tmpl/default.php on line 13

The i changed modules/mod_uk_gallery/tmpl/default.php

from

// Joomla 6 compatibility: Detect and alias classes
if (class_exists('Joomla\CMS\Language\Text')) {
    // Joomla 3/4/5 or with compatibility plugin
    class_alias('Joomla\CMS\Language\Text', 'TextCompat');
} else {
    // Joomla 6 without compatibility plugin
    class_alias('Joomla\Language\Text', 'TextCompat');
}
to:

// Only create the alias if it hasn't been defined yet
if (!class_exists('TextCompat')) {
    if (class_exists('Joomla\CMS\Language\Text')) {
        // Joomla 3/4/5 or with compatibility plugin
        class_alias('Joomla\CMS\Language\Text', 'TextCompat');
    } else {
        // Joomla 6 without compatibility plugin
        class_alias('Joomla\Language\Text', 'TextCompat');
    }
}

this fixes the Problem.

Can you add it in futre Updates?