Hi there.
I can help you setup a secure Bitrix24 instance.
I will use a reverse proxy (Nginx proxy manager) and deploy your apps in docker containers. This will give you more security, super easy to expand and you can easily manage your server via web. You will be able to add new apps and setup domain, subdomain with auto SSL via Lets encrypt or use custom SSL cert. I can also add your website to Cloudflare for extra protection, cache, proxy, etc. (Cloudflare Free tier is not bad at all).
I will also use docker container for any other applications you want running on your server. Any tool i use is free open source. Lets talk.
Best regards,
Daniel Preugschat