On-Prem Exchange Server. Way better than anything else.

Install a hypervisor.

Install best desktop OS in one VM.

Install best Server OS in another.

Another vote for Bookstack. We’ve been using it in a business for years now. Easy to setup and configure. Easy to use. Just works.

Start with requirements, not a solution.

What thing/service do want to add/improve that will make your life better. Not a product, think concepts.

Once you know what to require, select a product that meets your requirements. Build your computer accordingly.

OrangeHRM has a free tier.

It is a mammal that cries when it is unhappy:

Look at baby monitors.