As someone who’s set up and managed critical business applications I would say that it’s perfectly fine to host your own provided you have decent hardware that’s capable of doing what you need and as a dedicated business line to provide connection.

If you try to run mission critical business applications on a home internet connection you’re going to have a really bad fucking time. But hosting business critical applications on appropriate hardware and a 1Gb/s business connection with an SLA is going to meet 95-98%% of all business applications.

If something like that sounds expensive or too difficult to do then it’s too expensive or too difficult for you to host yourself. Just go with a provider and sidestep self-host.

Debian, baby.

Chest freezers are exceptionally energy efficient. It’s not a very good comparison.