So, exploring a bit more about VMMs, I found that OpenBSD, need to improve the CPU usage in VMMs, between each machine. I mean: while testing, I found that each VMM will use one core at 100% and the ammount of memory that I specify to each VM to use. That is not so good, since the CPU don't need to be at it's limits all the time, but being used when is needed, while memory is the same. The main host have a waste of CPUs and Memory that are defined to be used in VMs. I don't really know if this is good or not, but since I am not an expert I can speculate about what is or what is not. "The ones who don't know, can do mistakes and the ones who know, can do mistakes too."
So, I think this behavior is not the same for QEMU, since we emulate each hardware, including the CPU, while VMMs are Virtualization too, this "how much each machines can use from the main host", should be more soft. Like: you can use this CPU but you should know how to use it. I can have a 386 and the system will not use that single CPU at 100% all the time. I think this problem can be about the multi-threading, that they try to remove/disable from OpenBSD systems, while that, remove that "good feeling", that things happen faster. In fact, by what I could read and listen, the Multi-threading feature is a security hole and based on that, they disable it by default, while the development of OpenBSD have that in mind for years.
I guess the explanation from experts is here.
FreeBSD is not so paranoid with security, while offering the same features, the code can run vms in a soft way? I don't know, but I will test it. So, even if I am a Linux user for more than 20 years, I think I will give a change to FreeBSD on this virtualization aspect, to see if VMMs don't consume so many resources as they do in OpenBSD.
FreeBSD and OpenBSD, open on me the curiosity to explore them, while I can try to do the same with Dockers in Linux. Sadly, most Linux distros use Systemd, while the ones that use OpenRC are hard to maintain, like the default installation of Gentoo. I think Slackware uses OpenRC too, but I don't know, if Slackware team, develop something to update/upgrade the system. For years, they didn't have any tool for that propose. Anyway, Debian and Ubuntu-Server are normally recommendations, while most users see this two Distros, as simple and fast.
Is a difficult choice, but I will continue to test each, to have a better idea of what works for me or not, while learning something new.