Well, I did that but I'm not sure if it was the solution. I observed that the indexed files were going up, while the index said it was paused. Really strange.
I also did a modification on the "Local Policy Group":
https://appuals.com/windows-11-indexing-is-paused/#:~:text=Indexing%20is%20paused%20by%20local,re%20on%20battery%2Dsaving%20mode.
According to this, I should set it in "Disable".

In the Spanish version, the description says the opposite:

It says: if disables, the index is paused each time that the PC runs from battery. So description is opposite of what it is written in the english version.
So I decide to set it to Enable.
Anyhow, with this 2 changes, index finished this morning. My laptop has been plugged all the time. Today I worked all the day, checking index from time to time and it didn't pause. Increasing the index a bit because new files, emails, etc. So it feels normal.
I will double check during the next days and let you know.
Regards,