org-mode not producing plots with python source blocks

I'm trying to use org-mode to knit a document with some text and plots produced with python. However, when I export the org file to html or pdf, it doesn't output the plots, only the text and code.

I even used the example code in https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-python.html (for both pre 9.7 and post 9.7), but it produces only the code and not the plots:

* #+title:TEST
#+author: Author

#+begin_src python :session :results file link
import matplotlib
import matplotlib.pyplot as plt
fig=plt.figure(figsize=(3,2))
plt.plot([1,3,2])
fig.tight_layout()

fname = 'images/myfig.pdf'
plt.savefig(fname)
fname # return this to org-mode
#+end_src

#+RESULTS:
[[file:images/myfig.pdf]]

#+begin_src python :results file link
import matplotlib, numpy
matplotlib.use('Agg')
import matplotlib.pyplot as plt
fig=plt.figure(figsize=(4,2))
x=numpy.linspace(-15,15)
plt.plot(numpy.sin(x)/x)
fig.tight_layout()
plt.savefig('images/python-matplot-fig.png')
return 'images/python-matplot-fig.png' # return filename to org-mode
#+end_src

#+RESULTS:
[[file:images/python-matplot-fig.png]]

#+begin_src python :results graphics file output :file boxplot.svg
  import matplotlib.pyplot as plt
  import seaborn as sns
  plt.figure(figsize=(5, 5))
  tips = sns.load_dataset("tips")
  sns.boxplot(x="day", y="tip", data=tips)
#+end_src

#+RESULTS:
[[file:boxplot.svg]]

#+begin_src python :results graphics file value :file boxplot2.svg
  import matplotlib.pyplot as plt
  import seaborn as sns
  plt.figure(figsize=(5, 5))
  tips = sns.load_dataset("tips")
  sns.boxplot(x="day", y="tip", data=tips)
  return plt.gcf()
#+end_src

#+RESULTS:
[[file:boxplot2.svg]]

All the files are created in the images directory, and are OK. However, when exported to html, the output is this:

I have This in my .emacs:

(org-babel-do-load-languages
 'org-babel-load-languages
 '((python . t)
   (R . t)
   (shell . t)))

I'm working with emacs 29.4 and M-x org-version 9.6.15, Python is 3.10.12, elpy 20240109.1445 and jedi 20191011.1750.

What am I missing?

Edit:

I checked Saving Python matplotlib figures with source-code blocks but couldn't solve the problem.