Yes, Ubuntu is based on Debian, and it can upgrade without full reinstalls
thanks mostly to its much more complete dependency tree.  My home Debian
system has been upgraded many times over the past almost 20 years.  The
only problem is that it is 32-bit, and upgrading from 32-bit to 64-bit
is much more challenging so I haven't been willing to take that jump.
There are web pages that show how to do it though.

Dave

On Fri, May 22, 2020 at 02:59:15PM -0700, Yasha Karant wrote:
> I need to upgrade my wife's machine from Ubuntu 18 LTS to 20 LTS at the
> earliest convenient time (that may be after the end of this academic term to
> avoid disruption).  She runs Ubuntu on her 2-in-1 as evidently SL 7 does not
> support all of the hardware functionality that she needs.  I have found a
> URL with detailed instructions that I am willing to forward the information
> as a PDF to whomever has done this and is interested.  My understanding is
> that unlike EL that more or less requires a new install to go from EL N to
> EL N++, Ubuntu will upgrade in place.  If anyone has done this, please
> reply, preferably off list to [log in to unmask] so that any URLs will not be
> "modified" by the security filters at my university.
> 
> Take care.  Stay safe.
> 
> Yasha Karant