Clean & Restore WordPress Site

My decade-old WordPress site is currently down because the most recent backup contains malware. I have another clean backup ready, and I want the site restored from that version with all malicious code removed.

Here’s what I need from you:
• Safely restore the site from my clean backup.
• Scan both the database and file system to ensure no malware remains.
• Verify that pages, posts, themes, and plugins load correctly after the restore.
• Recommend simple, budget-friendly security steps (e.g., essential hardening tips, a free or low-cost firewall plugin) so I can avoid repeat infections.

Please let me know your process and the estimated time to complete the task.