I got an e-mailing from the FAA that said, among other things:

New editions of all FAA aeronautical charts are now available for pdf
download every 56 days.
https://www.faa.gov/air_traffic/flig..._Products/vfr/

The previous editions of the sectionals are dated on that page at
various dates in 2020, while all of the "next edition due" dates seem to
be today (Feb. 25, 2021). New faster refresh cycle? Cool.

But the files offered for download are still the old, well, sectionals,
i.e., the sections of the country that were covered by the old paper
sheets. And the file types offered are GEO-TIFF and PDF. Plain image
files apparently not.

Of course our gliderport is right near the seam between two sections.
In the past few years I've been downloading the two sheets, converting
to image files, reducing resolution, cropping to very carefully include
the same longitude range on the seam, and then electronically glueing
them together into one image file. (Which I then keep on my cellphone.)
This is a lot of work, and the results are not perfect, there are
anomalies along the seam. And all this seams/seems silly in 2021.

So, is there any way I can download a seamless "sectional" for my chosen
flying area (overlapping those antiquated sections)?

I've asked this before, but so far I have no solution. There are some
web sites that display sectionals on the screen seamlessly, but you
can't download a chart, only what you can see on the screen (small area
or low resolution).

Alternatively is there easy to install and use software that can import
the downloadable GEO-TIFFs and generate across-seams charts? Such
software clearly lives inside those web sites that show seamless charts.
People who use software such as ForeFlight have it inside their iPads.
I want it in my PC so I can create plain image files that I can store
on any device.