No it is not. I self-host on my hardware and regularly consider moving some services to a VM hosted by someone else. It would still be self-hosting because I am in control of the service.
If you want to have a truly service "by you" this is going to be complicated to rewrite (or review) the applications and OS and build your own hardware from something arbitrarily defined as "scratch".
It sounds very much like the discussions of audiophiles about golden cables and what not - while others listen to the music for the pleasure of listening.
