<?php

$original = [
	[
    	'id' => 1,
    	'title_ru' => 'Сиделка',
        'description_ru' => 'Уход за пожилыми людьми, помощь больным и не самостоятельным',
        'title_en' => 'Nurse',
        'description_en' => 'Care for the elderly, the sick and not an independent',
    ],
    [
        'id' => 2,
        'title_ru' => 'Уборки',
        'description_ru' => 'Уборки домов, уборка квартир и офисов, уборка в подъезде',
        'title_en' => 'Cleaning',
        'description_en' => 'Cleaning houses, cleaning offices and apartments, cleaning in the stairwell',
    ],
];

$filtered = [];
foreach ($original as $block_key => $block) {
    $filtered[$block_key] = array_filter($block, function ($key) {
        return ($key === 'id') || preg_match('/_ru$/', $key);
    }, ARRAY_FILTER_USE_KEY);
}

var_dump($filtered);