Dedicated server cleaning from malware

Cleaning a server with several malwares, the server hosts 30 websites, many of them are WordPress, others Prestashop e-commerce. The malware attacks several files, including the index.pho where lines of code are written, which modify the homepage of the website, also creating redirects to other websites.
An experienced freelancer is required to COMPLETELY clean the server PERMANENTLY. Linux server running Virtualmin.