I think is the GPU that takes some seconds to switch modes, signal over HDMI/DisplayPort. So the true value of 20 secs is respected.
If I unplug one of my monitors, it doesn't show me anything, no boot menu, a blank screen until I found that Devuan is started. I have a new GPU: AMD RX 9060 XT, 16GB. I didn't have such issues with my old AMD 4GB card. So, if I have my both monitors switched on I have the boot menu. I'll leave like this, and maybe I will found out a reason sometime.

So, to conclude and close this post, I have created for myself a Gitea account on Devuan Git Store and published the project there:
https://git.devuan.org/ovi/devuan-knowledge_base

I will try to bring it to an usable form, in time. I have in mind users like me, that are new to Linux and Devuan especially, or migrated from another distribution and that want to know more about the Devuan Operating System, in general.
I know that Devuan has its own wiki, but it just doesn't fit for my project idea and also I don't like it, to be honest.

There are many good, general topics inside the forum that can have place in my devuan-knowledge_base. I will look for them and add them there.

So, who knows, maybe over one, two years if somebody from Devuan team consider that the content make sense for the general public, the repo will be always there.Just take the public folder, correct, throw away what is unecessary and that's all.
If somebody wants to have a look time to time, criticize, add corrections, ideas, etc. I would be glad to hear them. Is only one package to install.
But not so soon , there is nothing inside yet, just a sketch with some blank pages.

Finally, my strong opinion is that any good product needs to have a simple HandBook, accessible to anyone.

No problem. English is not my native language. so.. I don't know if this kind of punishment is still a practice, but it was, indeed .
Is getting late on my part of the world and soon will be Monday (job, kids, family and so on...)
Thanks again for your answers!

I haven’t thought so far, not now. In the beginning I just want to have my own corner of internet first, use something quick as Hugo static site generator. Hugo, has its own learning curve, more work is on creating the skeleton, but then the content are just simple md files, so the content creator (to say so) can focus on the content it self, not on the html/css, linking pages and so on.

I see that Devuan wiki is using PmWiki and I think it has also kind of translator from md files in their own format. So, who knows, maybe in the future I would be glad to have my information stored in the Devuan Wiki. But today, I have nothing more than a foundation to add my notes and publish them, no valuable content. Maybe, in the end my content is just a garbage that doesn’t have a place in an official wiki.

I use labwc (the OpenBox replacement in Wayland). They have their wiki on GitHub pages. And is pretty good as a content. That’s why I was thinking on  GitHub pages.

But, before anything else, I need first the agreement of Mr. Denis Roio (jaromil) as Mr. Ronnquist advised and the content it self. Then, for hosting Calamity suggested some variants. But then will see, still is a long way. But I know where to start.

For sure I will have technical questions for my small wiki, and I will ask them, here, on the forum.

Thank you all for the support!

First, Thank you for your response!

I know that Mr. Denis Roio (jaromil) is an important person in the Devuan project. I didn't know exactly his role.
I started this more like a personal project, first time when I did a site by myself and I choose github from the technical point of view: is simple, free as long as the repository is public, it has all the needed infrastructure to run such a small project and I don't know anything about hosting . Yes, in the end maybe is not the best idea to host it there. Still, I am happy that my test succeeded, in the end and I saw that can be done. Now I made the repo private and the site is offline.
I wouldn't abandon my idea. I still think a small handbook for Devuan will be useful, for myself sure it is. Probably I will try to contact Mr. Roio.

I tried also XLibre with OpenBox. And I found after installation a weird mouse cursor. Then I found that it was reported as bug. I think is still a young project. Probably is nice to run, but not on a main machine. I am running Wayland with labwc and I kind of like it. Despite some or other says, Wayland shows some improvements compared with X11. Is still have some limitations, that's true also.

Ubuntu: please, rust in peace!

To maintain accuracy of your system's clock you can use "chrony". It will enable also a dedicated service.

If you run only Devuan is enough to install the "chrony" package.

If you are dual-boot with Windows it's recommended to have both system set to UTC time. Windows does not use UTC by default, and if you are dual-booting, this will conflict with Devuan.  That's why the installer will see that you have Windows installed and will set the time as Windows to local time.
To  make the system time to UTC in Windows just download and run the registry file that RedGreen925 suggested.
In Devuan do this:

Check if the system time is set to UTC or not:
$ cat /etc/adjtime

Marks the hardware clock standard as UTC in Devuan and verify
$ sudo hwclock --systohc --utc
$ cat /etc/adjtime

Force chrony to  re-sync:
sudo chronyc makestep

I succeeded installing  stable version and then switched to Freia.

I have seen that the ISO is now available. I tested the Freia installer on junk laptop ( junk because it has some issues from factory, but mainly functional). Indeed Partition Disks is failing also on real hardware. Now I see why the ISO image was missing.

I still have one question: on the Testing(now Freia) should I run time to time: apt full-upgrade?

Thank you all for your answers!