Hello Ofi,
Thank you very much for your observation which I implemented by moving the text block, and it's ok!!! Advanced search finds the text “sauna”.
I still have to spot and correct all the other anomalies... because I realize that there is a lot of text that is not found on many pages.
And I realize that it is enough for a block of text to be placed in a line for us to not be able to find this text, even when the lines are not nested!!!
It's still annoying that the advanced search does not find these texts placed in text blocks below the lines!
I don't (yet) master SP Page Builder, and it was someone else who created the pages of my site with SP Page Builder that he seemed to master...
I have the impression that this is a fault of SP Page Builder...
Thanks again.