Next cloud rapsberry pi 4 installation issue

I am trying to download the latest nextcloud with php7.3 when i access the nextcloud url once its extracted i am seeing below error. please help me

<?php /** * @copyright Copyright (c) 2016, ownCloud, Inc. * * @author Georg Ehrke * @author Joas Schilling * @author Jörn Friedrich Dreyer * @author Lukas Reschke * @author Morris Jobke * @author Robin Appelman * @author Roeland Jago Douma * @author Sergio Bertolín * @author Thomas Müller * @author Vincent Petry * * @license AGPL-3.0 * * This code is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License, version 3, * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License, version 3, * along with this program. If not, see * */ require_once __DIR__ . '/lib/versioncheck.php'; try { require_once __DIR__ . '/lib/base.php'; OC::handleRequest(); } catch(\OC\ServiceUnavailableException $ex) { \OC::$server->getLogger()->logException($ex, array('app' => 'index')); //show the user a detailed error page OC_Template::printExceptionErrorPage($ex, 503); } catch (\OC\HintException $ex) { try { OC_Template::printErrorPage($ex->getMessage(), $ex->getHint(), 503); } catch (Exception $ex2) { try { \OC::$server->getLogger()->logException($ex, array('app' => 'index')); \OC::$server->getLogger()->logException($ex2, array('app' => 'index')); } catch (Throwable $e) { // no way to log it properly - but to avoid a white page of death we try harder and ignore this one here } //show the user a detailed error page OC_Template::printExceptionErrorPage($ex, 500); } } catch (\OC\User\LoginException $ex) { OC_Template::printErrorPage($ex->getMessage(), $ex->getMessage(), 403); } catch (Exception $ex) { \OC::$server->getLogger()->logException($ex, array('app' => 'index')); //show the user a detailed error page OC_Template::printExceptionErrorPage($ex, 500); } catch (Error $ex) { try { \OC::$server->getLogger()->logException($ex, array('app' => 'index')); } catch (Error $e) { http_response_code(500); header('Content-Type: text/plain; charset=utf-8'); print("Internal Server Error\n\n"); print("The server encountered an internal error and was unable to complete your request.\n"); print("Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.\n"); print("More details can be found in the webserver log.\n"); throw $ex; } OC_Template::printExceptionErrorPage($ex, 500); }

This is for Debian 10 Buster. I think php is not correctly installed. List php-packages:
dpkg -l |grep php

Install missing packages from this installation guide. You can cut and paste the “apt-get” - line.