WordPress Bug Fixes & Disk Optimization

I am hosting 7 websites on HostGator.in shared hosting. My cPanel shows approximately 163 GB of disk usage, with most of the space consumed by the public_html directory. I am also experiencing intermittent 504 Gateway Time-out errors and File Manager loading issues... (Budget: ₹600 - ₹1000 INR, Jobs: cPanel, HTML, PHP, Web Development, Web Hosting, Website Design, Website Optimization, WordPress, WordPress Design, WordPress Plugin)