New questions should be posted as a new topic. Other possibly helping readers could miss your question because they just see a "Greeting" topic.

One problem - one topic, with a good summary as topic title - this is the best here.
Regarding your question,
sudo dpkg -l lists installed packages,
sudo dpkg -l | grep tex could show TeX packages and bundles. However, TeX would tell you if a package would be missing.
In the specific case, you could additionally use
Stefan