I have been using my current setup for some three months and it seems the mix is not that stable.

My original installation was Ubuntu 20.04/Gnome. On top of that, I loaded KDE Plasma 5.18.5. but every few days, starting the PC in the morning, the desktop UI reverts to Gnome, my icons are moved and the clock and weather widgets are gone and I need to spend some 20 minutes to put it all back.

So, I decided to move to KDE Neon Plasma as a new installation.

Any tips on how to go about it?
I will of course have a backup of all my files and directories, but can't see a way to save me reinstalling all my apps again.

I see no point in doing a full system backup, the new OS will not be happy if I restore the old system on top of it.

Any thoughts?

Cheers
Alex

KDE is a desktop environment, not an OS. Ubuntu is an OS, but not a desktop environment.
Most probably you want to switch from Gnome to KDE. I guess you need to make only KDE your default desktop and that's all, everything is installed.

I would recommend you to follow this: https://itsfoss.com/install-kde-on-ubuntu/

Did you only read the title and skip the post content?

KDE Plasma is a desktop environment. KDE Neon is a Ubuntu-based OS.

Alex has already switched from Gnome to KDE Plasma within Ubuntu and is having issues, so now wants to try KDE Neon instead.

Yes, that is just longer. and need to save/backup things. From the other hand installing that is quite simple again: [url]https://neon.kde.org/download[/url (I wouldn't ask the download link here).

On a normal installation, of whichever distro, one can choose the desktop environment to start up, if multiple DEs are installed. Typically that's an icon in the top right corner. It's also usually the default action to start the last DE in use, but that can be changed. I have no idea how Alex is set up, but it shouldn't be necessary to change distro just to stay with one desktop. Gnome can be uninstalled, but with its deep dependencies it's risky. OTOH, there is nothing wrong with changing distros. Lots of people distro-hop regularly. Having a separate /home partition makes it easier, because one can install the root filesystem, /, and keep the same /home partition, thus keeping one's personal data and settings. But without an existing /home partition, the only possibility is reformatting everything, possibly installing a separate /home in the process to deal with future reinstallations. Home is the only thing which really needs to be backed up unless the object is to do a complete reinstallation of the current system.

Why don't you just convert your Ubuntu install into a kde-neon install? Install the Neon certificates, add the neon repos, install the neon-desktop metapackage, uninstall gdm3 and all the gnome apps. Reboot and you'd be running Neon. While not supported, I've done it before and it works just fine.

Well good people,

From previous experience here in this fantastic forum, and due to the nature of the OS, I excpected to get many and varying feedbacks. I have already done the exercise of moving from Ubuntu to KDE Neon on my My Surface Pro 3 and it worked fine, with just two problems: Not holding network connection and not shutting down, both fixed now.

I do not intend to have multiple DE's, nor multiple partitions.

So, I will just backup my own things and install KDE Neon, same as I did on the laptop.

Thank you all for your feedback

Cheers
Alex