Half of the sidebar vanished

Hello,
Weird surprise : more than half of my side bar has disappeared ! Missing sections : search, about me, instagram,etc. The only thing remaining is the “recent post” widget, but the thumbnails pictures are also gone ??
Everything is updated on the blog, WP, TOTAL theme and plugins. The only recent change was activating Rank Math plugin (but if I deactivate it the matter is still there, so it seems not to be related).
Have you any idea of what could have happened, and how to fix that and get the complete sidebar back, as it was before ? Is restoring an older version of the database would help ?
Thanks a lot

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