Failing to configure tex-common on Ubuntu 20.04.2 LTS

I have had a problem with my Software Updater for some time, for some reason it was producing an error message saying the problem was coming from tex-common. I can not reproduce this error because I managed to fix it, I fixed it by removing tex-common and running software updater successfully. But then I got a problem when trying to reinstall my latex environnement. When I run: sudo apt-get install 'texlive-*' the installation process starts alright but at the end I get:

Running updmap-sys. This may take some time... done.
Running mktexlsr /var/lib/texmf ... done.
Building format(s) --all.
    This may take some time... 
fmtutil failed. Output has been stored in
/tmp/fmtutil.2mboIsZN
Please include this file if you report a bug.

dpkg: error processing package tex-common (--configure):
 installed tex-common package post-installation script subprocess returned error exit status 1
Processing triggers for install-info (6.7.0.dfsg.2-5) ...
Processing triggers for fontconfig (2.13.1-2ubuntu3) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu3) ...
Processing triggers for mime-support (3.64ubuntu1) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Errors were encountered while processing:
 tex-common
E: Sub-process /usr/bin/dpkg returned an error code (1)

I have tried sudo dpkg -C, I get:

The following packages are only half configured, probably due to problems
configuring them the first time.  The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 tex-common           common infrastructure for building and installing TeX

The command sudo dpkg --configure tex-common fails with a similar message as the first one:

Setting up tex-common (6.13) ...
Running mktexlsr. This may take some time... done.
Running mtxrun --generate. This may take some time... done.
Running updmap-sys. This may take some time... done.
Running mktexlsr /var/lib/texmf ... done.
Building format(s) --all.
    This may take some time... 
fmtutil failed. Output has been stored in
/tmp/fmtutil.il5mWMsU
Please include this file if you report a bug.

dpkg: error processing package tex-common (--configure):
 installed tex-common package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 tex-common

I have tried sudo apt-get install --reinstall tex-common, I got an message ending with:

0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
E: Internal Error, No file name for tex-common:amd64

I have found a very similar issue on this forum from 2 months ago (Incomplete update of tex-common during 20.04.2 upgrade), but the problem was fixed by: "Installing texlive-formats-extra (and a number of other packages triggered by that) seems to have cleared things up. Thanks, " Now this didn't work for me, When I try to install texlive-formats-extra I get the same error message that fmtutil failed..

The command apt-cache policy tex-common outputs:

tex-common:
  Installed: 6.13
  Candidate: 6.13
  Version table:
 *** 6.13 500
        500 http://fr.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        500 http://fr.archive.ubuntu.com/ubuntu focal/universe i386 Packages
        100 /var/lib/dpkg/status

The /tmp/fmtutil.il5mWMsU file is 15500 lines long, the last lines are:

  148 for language 4
  54 for language 3
  2 for language 1
  181 for language 0
No pages of output.
Transcript written on uplatex-dev.log.
fmtutil [INFO]: log file copied to: /var/lib/texmf/web2c/euptex/uplatex-dev.log
fmtutil [INFO]: /var/lib/texmf/web2c/euptex/uplatex-dev.fmt installed.
fmtutil [ERROR]: running `pdftex -ini   -jobname=pdfjadetex -progname=pdfjadetex *pdfjadetex.ini </dev/null' return status: 1
fmtutil [ERROR]: returning error due to option --strict
fmtutil [ERROR]: running `pdftex -ini   -jobname=jadetex -progname=jadetex *jadetex.ini </dev/null' return status: 1
fmtutil [ERROR]: returning error due to option --strict
fmtutil [INFO]: disabled formats: 1
fmtutil [INFO]: successfully rebuilt formats: 50
fmtutil [INFO]: failed to build: 2 (pdftex/pdfjadetex pdftex/jadetex)
fmtutil [INFO]: total formats: 53
fmtutil [INFO]: exiting with status 2

The command which pdftex returns /usr/bin/pdftex. The command pdftex --version returns:

pdfTeX 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian)
kpathsea version 6.3.1
Copyright 2019 Han The Thanh (pdfTeX) et al.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.37; using libpng 1.6.37
Compiled with zlib 1.2.11; using zlib 1.2.11
Compiled with xpdf version 4.01

The command which jadetex; which pdfjadetex; jadetex --version; pdfjadetex --version; dpkg -S jadetex.ini; sudo find / -type f -name "*jadetex.ini" returns:

/usr/bin/jadetex
/usr/bin/pdfjadetex
pdfTeX 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian)
kpathsea version 6.3.1
Copyright 2019 Han The Thanh (pdfTeX) et al.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.37; using libpng 1.6.37
Compiled with zlib 1.2.11; using zlib 1.2.11
Compiled with xpdf version 4.01
pdfTeX 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian)
kpathsea version 6.3.1
Copyright 2019 Han The Thanh (pdfTeX) et al.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.37; using libpng 1.6.37
Compiled with zlib 1.2.11; using zlib 1.2.11
Compiled with xpdf version 4.01
texlive-formats-extra: /usr/share/texlive/texmf-dist/tex/jadetex/base/pdfjadetex.ini
texlive-formats-extra: /usr/share/texlive/texmf-dist/tex/jadetex/base/jadetex.ini
[sudo] password for XXXXXX: 
/usr/share/texlive/texmf-dist/tex/jadetex/base/pdfjadetex.ini
/usr/share/texlive/texmf-dist/tex/jadetex/base/jadetex.ini
find: ‘/run/user/1000/doc’: Permission denied
find: ‘/run/user/1000/gvfs’: Permission denied

I didn't change the ini-files manually. I do not know what they are, is it possible for me to have changed them inadvertently?

I had problems with updating tex-common via apt because of locale issues too. I found that doing it in a tty outside of my desktop environment worked, whereas inside a terminal in the desktop environment (KDE Plasma, Ubuntu LTS 22.04) didn't, which led me to believe that the locales set in the desktop environment were confusing the update process.