I have a Mac Mini that I'd like to convert to a remote server (i.e. so when I am in a random coffeeshop I can connect to it to run computationally intensive tasks as it sits on my desk at home). Are there any fairly straightforward tutorials that explain how to do this?
For private use, a product like TeamViewer could be used, but for a more integrated solution you would need more knowledge (which can be attained for free) to setup and maintain a server.
There used to be a simple solution using iCloud’s Back to my Mac, but that is phased out as far as I know. (https://support.apple.com/en-gb/HT208922)
Running a remote desktop session without strong encryption is not recommended and leaves you vulnerable to assorted attacks, so a self-supported setup will be more involved than you might imagine.