It took a while, my timing predictions were totally wrong, but finally the Blog extension is available for TYPO3 10. Thanks to this how-to: https://docs.typo3.org/p/t3g/blog/master/en-us/Setup/Manual/Index.html, I was able to install this extension in no time. Probably the setting I used is not optimal, but I will try to improve it over time.
In the meantime I had tried to use other extensions for this blog, but unfortunately none of them satisfied me. One even required the modification of the MySQL database configuration, which was unthinkable, immediately discarded!
Now I have to try to recover the old posts and put them back in this blog, it shouldn't be too difficult thanks to the modularity of TYPO3.
See you soon...