Generating add_settings_section() calls dynamically

Question

Try this instead:

function settings_sections() {
    // array containing settings identifiers
    $array = ( 'SOMETHING', 'SOMETHING2', 'SOMETHING3', 'SOMETHING4' );

    // loop through settings identifiers and generate settings sections
    foreach( $array as $v) {
        add_settings_section(
            $v . '_settings',
            $v . ' Settings',
            'generate',
            $v . '_page'
        );    
    }
}

echo outputs a string, you should just be calling add_settings_section() directly from inside the loop.

Also, NB: generate() is not the best name for a function, you should really go with something that’s less likely to overlap with another function (prefix it with something)