Impossible to have the curve that I want because when closing the line, the curve changes completely and if I do "Enter" the curve is not closed
Is there a keyboard shortcut to close the curve at the starting point?

I'd try holding the Shift key when closing the path, it will look wrong until you release the mouse button.

http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-LivePathEffects-SpiroSpline.html

Thank you Tyler
I had tried ctrl,shift and alt but not successful.
I'm going to restart....😏

Using Shift-click on the closing node:

Ok OK that works😊

Thanks for the link because, although I have created folders in my bookmarks, I sometimes have trouble finding my way around...😉
I used the spiro because I was following a tuto but finally I will use the BSpline path seems easier, or the first option by converting the hard nodes...