RealUrl Multidomain setup with configuration for tx_news. You could copy & paste the code, but it's important to change line 4 and line 133. Replace the domain name and the PAGE_UID. In line 133 it's needed to replace the PAGE_UID with the page number of the detail news page.

realurl_conf.php

<?php

$domainConfiguration = [
    'www.first-domain.com' => PAGE_UID,
    //'www.second-domain.com' => PAGE_UID,
    //'www.third-domain.com' => PAGE_UID
];

$txRealUrlConfiguration = [
    'init' => [
        'appendMissingSlash' => 'ifNotFile'
    ],
    
    'fileName' => [
        'defaultToHTMLsuffixOnPrev' => true,
        'index' => [
            'rss.xml' => [
                'keyValues' => [
                    'type' => '100'
                ]
            ],
            'rss091.xml' => [
                'keyValues' => [
                    'type' => '101'
                ]
            ],
            'rdf.xml' => [
                'keyValues' => [
                    'type' => '102'
                ]
            ],
            'atom.xml' => [
                'keyValues' => [
                    'type' => '103'
                ]
            ]
        ]
    ],

    'pagePath' => [
        'rootpage_id' => '1'
    ],

    'preVars' => [
        [
            'GETvar' => 'no_cache',
            'valueMap' => [
                'nc' => '1'
            ],
            'noMatch' => 'bypass'
        ],
        [
            'GETvar' => 'L',
            'valueMap' => [
                'en' => '1'
            ],
            'noMatch' => 'bypass'
        ]
    ],

    'fixedPostVars' => [
        'newsDetailConfiguration' => [
            [
                'GETvar' => 'tx_news_pi1[action]',
                'valueMap' => [
                    'detail' => ''
                ],
                'noMatch' => 'bypass'
            ],
            [
                'GETvar' => 'tx_news_pi1[controller]',
                'valueMap' => [
                    'News' => ''
                ],
                'noMatch' => 'bypass'
            ],
            [
                'GETvar' => 'tx_news_pi1[news]',
                'lookUpTable' => [
                    'table' => 'tx_news_domain_model_news',
                    'id_field' => 'uid',
                    'alias_field' => 'IF(alternative_title != "", alternative_title, title)',
                    'addWhereClause' => ' AND NOT deleted',
                    'useUniqueCache' => 1,
                    'useUniqueCache_conf' => [
                        'strtolower' => 1,
                        'spaceCharacter' => '-'
                    ],
                    'languageGetVar' => 'L',
                    'languageExceptionUids' => '',
                    'languageField' => 'sys_language_uid',
                    'transOrigPointerField' => 'l10n_parent',
                    'expireDays' => 180
                ]
            ]
        ],

        'newsCategoryConfiguration' => [
            [
                'GETvar' => 'tx_news_pi1[overwriteDemand][categories]',
                'lookUpTable' => [
                    'table' => 'sys_category',
                    'id_field' => 'uid',
                    'alias_field' => 'title',
                    'addWhereClause' => ' AND NOT deleted',
                    'useUniqueCache' => 1,
                    'useUniqueCache_conf' => [
                        'strtolower' => 1,
                        'spaceCharacter' => '-'
                    ]
                ]
            ]
        ],

        'newsTagConfiguration' => [
            [
                'GETvar' => 'tx_news_pi1[overwriteDemand][tags]',
                'lookUpTable' => [
                    'table' => 'tx_news_domain_model_tag',
                    'id_field' => 'uid',
                    'alias_field' => 'title',
                    'addWhereClause' => ' AND NOT deleted',
                    'useUniqueCache' => 1,
                    'useUniqueCache_conf' => [
                        'strtolower' => 1,
                        'spaceCharacter' => '-'
                    ]
                ]
            ]
        ],

        'PAGE_UID' => 'newsDetailConfiguration',
        //'PAGE_UID' => 'newsCategoryConfiguration',
        //'PAGE_UID' => 'newsTagConfiguration'
    ],

    'postVarSets' => [
        '_DEFAULT' => [
            'controller' => [
                [
                    'GETvar' => 'tx_news_pi1[action]',
                    'noMatch' => 'bypass'
                ],
                [
                    'GETvar' => 'tx_news_pi1[controller]',
                    'noMatch' => 'bypass'
                ]
            ],

            'dateFilter' => [
                [
                    'GETvar' => 'tx_news_pi1[overwriteDemand][year]',
                ],
                [
                    'GETvar' => 'tx_news_pi1[overwriteDemand][month]',
                ],
            ],
            
            'page' => [
                [
                    'GETvar' => 'tx_news_pi1[@widget_0][currentPage]'
                ]
            ]
        ]
    ]
];

foreach ($domainConfiguration as $domain => $domainRootPageUid) {
    $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['realurl'][$domain] = $txRealUrlConfiguration;
    $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['realurl'][$domain]['pagePath']['rootpage_id'] = $domainRootPageUid;
}