Website Malware Cleanup & Fix

My site https://kshomedecor.com.my/ has gone offline several times and the host keeps telling me it is infected. Each time I restore a backup it works for a while, then the problem returns. On top of that, the blog now shows a lot of text I never wrote, so I need the unwanted content removed and the whole installation checked thoroughly.

What I need right now is a full security clean-up that gets the site loading normally, removes every trace of malware, and clears out any injected or spam content in the blog section. Once clean, please harden the installation so the infection doesn’t come back—firewall rules, updated core/plugins, file-permission review, whatever best practice applies—then run a final scan to confirm everything is safe.

Please document the work you do and give me simple steps I can follow to keep things healthy in future.