Lately I ran across GitHub - wimpysworld/deb-get: apt-get functionality for .debs published in 3rd party repositories or via direct download 📦 and here is how it is described:
deb-get makes it easy to install and update .debs published in 3rd party apt repositories or made available via direct download on websites or GitHub release pages.
When some s/w is definitely very good I am happy to install it via Gdebi & its DEB file so DEB-GET's concept is very attractive to me for 'other' s/w that the system will not update on its own.
I have also preferred to use appimages ..BUT=>
I've had some very poor experiences when trying out appimages, so I now hesitate to get anything new just to test things out anymore.
That having been said, for s/w which I already have in regular use, I have found no tool (yet...) which can easily update some few apps, and deb-get does not have those in its list of supported apps.
Appimages are a prime example of this need for easy updating whilst maintaining any personalized stuff (like bookmarks in a browser, etc...).
Of the s/w that I have & use very regularly - LibreWolf is is at the very top of my wish list for easy updating, and short of re-downloading its appimage I've found no simpler method.
Other s/w I have & use which are not on the deb-get supported list are:
Another app which I and all my clients use is the Softmaker Freeoffice suite.
It is a superb way to use M$office files & has shown itself to be far more reliable & bug free than Libreoffice was when we all used it.
FreeOffice is a full-featured Office suite with word processing, spreadsheet and presentation software. It is seamlessly compatible with Microsoft Office and available for Windows, Mac and Linux.
It is listed here as experimental:
But I am not THAT trusting, besides which, we all already have its installed version.
Even though I avoid using these next 2, having some way to easily get & update them (OR appimage releases of them) would be very useful & greatly appreciated:
I don't have Flatpak installed & also prefer not bothering with Snaps.
AFAIC it would be very advantageous for most apps to have official & trustworthy appimages made of them - but that is just my 2 cents !!