To Remove Malwares On My Server

My server has been infected by malwares. On that server I have lots of files, domain names, and 3 websites. I need someone to download everything on their computer to remove all the malwares before uploading it back on mine. Once upload, I will ask my host to rescan again to confirm ZERO malware, then I will consider the task done. Please note that the 3 websites are from Joomla, opencart 3.0.3, php, html, css, js, Laravel. So you have to be able to remove malwares on these types of program. The last scan showed almost 21000 files infected.We have to shut everything down to stop the spread. Please send me your best quote with detailed description of how you will proceed. Have you done such job in the past? If yes please explain.