Wrong !!!! There is no "manual saving button" in EN.
I have my own website based in a CMS close to wordpress style and I know what you're talking about but it is not the case in EN.
Note should sync automatically in EN thus, in my case, with my 200MB fiber internet connexion, I should not be impacted by any performance issue.
Since many years, I'm using a bunch of Web Based App for many purposes like Trello or Lucidchart or google doc etc....So here, the issue seems to be in the "Permanent sync" feature? Without a specific diagnostic, it is not something you'd might to hazard a guess on.
Thank you anyway for your suggestion, I appreciate your help here. I have to admit there's a great assistance support in this forum and this is a very good point. I have to accept my data are lost and I've already started using the thick client now.