$text = '<span class="wpcf7-form-control wpcf7-acceptance">
<span class="wpcf7-list-item">
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
</span>
<span class="list-item">
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
</span>
<span class="wpcf7-list-item">
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
</span>
</span>';
$patterns = [
'~<span[^>]*wpcf7[^>]*>\s*(<input[^>]+>)\s*</span>~s',
'~<span[^>]*wpcf7[^>]*>(.+)</span>~s'
];
$text = preg_replace($patterns, '$1', $text);
echo $text;
/* Результат:
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
<span class="list-item">
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
</span>
<input type="checkbox" name="our-policy" value="1" aria-invalid="false" class="form-check-input" id="our-policy">
*/
$str = '<p>без атрибутов</p>
<p align="justify">с атрибутами</p>';
$res = preg_replace('~<\pL+\d?\K.*?(?=>)~', '', $str);
echo $res;
$text = "уменьшает силу\rразмаха.</div>\r\n</div>Также уменьшает...\r\nИ ещё текст";
$patt = "~(?<!</div>|</ul>|</li>)[\r\n]+(?!</?(?:div|ul|li)>)~";
$text = preg_replace($patt, "</p>\n<p>", $text);
echo $text;
$text = '90+3\' SGDGG p[gdsg] sadgcgbcvb';
echo preg_replace('~^[^a-z]+~i', '', $text);