deviant-art-proxy-function.php

<?php
function proxy_deviantart_oembed( $data ) {
	$url = $data->get_param( 'url' );
	if ( ! is_valid_url( $url ) ) {
		return new WP_Error(
			'error',
			'Error: not a DeviantArt URL',
			[ 'input' => $data ],
		);
	}

	$da_response = wp_remote_get(
		'https://backend.deviantart.com/oembed?url=' . $data->get_param( 'url' ),
		[ 'headers' => [ 'User-Agent' => 'WordPress OEmbed Consumer' ] ]
	);

	if ( empty( $da_response ) || 200 !== $da_response['response']['code'] ) {
		return new WP_Error(
			'error',
			'Error in response from DeviantArt',
			[
				'input'    => $data,
				'response' => $da_response,
			]
		);
	}

	return new WP_REST_Response( json_decode( $da_response['body'] ) );
}