I use almost simultaneously 2 machines and at least one VM, all are Linux Ubuntu, and not all have the same LO version as most came preínstalled…
If I try to remove the pre-installed LO, it wants to remove far more than just LO 
I wish to install a newer version and, more importantly, have that same on all machines
What is the preferred way to install a new version on Ubuntu and remove/disable/ignore older versions?
Unless you have good reasons, install the same Ubuntu version on all your machines (physical or virtual). This will load the same LO version. If you follow a strict upgrade policy, you’ll always be at the latest version for the given distribution, perhaps not the latest at libreoffice.org, but the latest guaranteed and tested by Ubuntu.
That is hard to do, some cannot even receive the newer Ubuntu version
Ubuntu LibreOffice packaging team PPA is a PPA of the team who create the distro package; and they maintain several PPAs for different versions (so that you can choose one that is supported across all your Ubuntu systems, even if they run different Ubuntu versions).
As they put it:
In general, this PPA is not for the average user to install without a closer look (if it would be, its packages would be in the main repositories). OTOH, it is way better to use packages from this PPA than using the *.deb files that The Document Foundation provides upstream, which are intentionally build against a very old baseline for maximum compatibility. So, if you want to be on the bleeding edge, do it here, not with upstream *.debs.
Note that if you use these PPAs, they update your installed LibreOffice, so no need to uninstall those - the usual Ubuntu updater will do everything itself.
Very good idea, I found here https://www.ubuntuupdates.org/ppa/libreoffice PPAs with 7.3.5 for 18.04/20.04/22.04
Thanks, I believe that is exactly what I wanted 
It just worked like a charm 
Now I have all 7.3.5
Thanks
Simply keep the old version and add the new one.
Ok but…
According to [Installing in parallel/Linux - The Document Foundation Wiki] I will then have to manually select the default path for every file type or open manually LO from /opt.
I have tried that in the past and there are more file types than I know of, so the old version keeps coming back.
Is there a script, or something, to reassign all file extensions or replace the old files with links, or whatever?
The latest installed version takes over the file associations.