Did you already read my post about FreeBSD? Based on the last experience on using Gentoo, I figure out that FreeBSD is what I need to develop my servers. I just need one single Machine to host all necessary services in different machines, while that would cost more electricity, by using FreeBSD I can have different "dedicated servers" inside the main server. Is what Jails stand for.
BSD systems are mind blowing. You can create several jails for many purposes, while the main purpose here is only to have a dedicated Operating System for each service, giving me the sensation that is a little bit more secure than having a real dedicate Operating System in a dedicated Hardware for each Service, or even deeper, you can create a jail with many child processes that are other jails.
Like in prison, to be in Jail is FreeBSD but that cost you some work to maintain it, like any prison will spend money to maintain the people inside the Jail, alive. There are several type of Jails, but building one or more in the original way ask you more work to configure and maintain. Therefor, using Bastille software is the recommendation to deal with this problem in a easy way.
So, you can have for example one machine with 1TB disk space and 8GB of RAM and 8 CPU cores that would be a dedicated server, but since "you" wish to add more services in a independent way from each others, you can create Jails. In OpenBSD you can do the same, but since OpenBSD is really paranoid with security, performance is sacrificed, while using FreeBSD performance is bigger and therefor you don't need to sacrifice half of your OS resources to use them.
Knowing all of this, make me think about this "little joke": The Internet is not the Internet, but a BSD system. In a conversation with some guys from #FreeBSD channel on irc.libera.chat IRC server, I learn a bit more about this approach and I feel I need to try it. Differently from Docker, BSD Thick Jails are not dependent from the main system. So, if an Hacker own the server, in fact the hacker only owns the Jail, not the main system. Naturally this can be false since security is a big big problem that can effect many things, but the base concept is that, which is pretty nice.