There is guaranteed support on packages found in main
which include all the packages found on Ubuntu Desktop/Server etc. ISOs.
There is no guarantee on packages from universe
or community supported beyond the 3 years, though all 'universe' packages can receive fixes during the normal 5 year cycle of a LTS by any MOTU, but teams offer only 3 years guaranteed support.
During the first three years of support; in my opinion there is no difference between Ubuntu with LXQt, and a Lubuntu system. You could also extend that to the full five year cycle (personally I'd call a Lubuntu system a Ubuntu system using LXQt after Lubuntu reaches EOL at the end of three years).
After LTS has ended; or after the five years though; you'll need to read the fine print of what packages are included. Canonical have published numerous 'indicators' which read like a very large number of packages; but we don't know how they are calculated. They've specified some architectures are included; some are excluded, but even with that detail, it's clear to see only a small subset of packages are included in Ubuntu Pro support guarantees.
If you're using a Ubuntu LTS release past it's five years of standard support, I'd personally opt to use the default desktop (GNOME for recent releases). This applies with 12.04 ESM, 14.04 ESM & 16.04 ESM (which used Unity 7 desktop by default). This 'opinion' is based on reading the various notices/blogs put out by Canonical on this matter.
In a number of months we'll get more details about Ubuntu 18.04 LTS as it transitions to ESM/UA support, and when the full list of packages that will receive support are available, my opinion may differ to what is now (which is based largely on prior 12.04, 14.04 & 16.04 facts). Whilst the number of packages has been increased significantly, we still don't know which packages are to be included on 18.04 and later ESM/UA support plans.
I want to buy Ubuntu Pro support from Canonical
- Ubuntu Pro is free for individuals for upto 5 machines. – Archisman Panigrahi Jan 11 '23 at 16:52I want to buy Ubuntu Pro support from Canonical. Will they support either config equally?
-- You should contact Canonical about it. In this site, volunteers (not Canonical employees) answer questions about Ubuntu. – Archisman Panigrahi Jan 11 '23 at 16:59