i do believe that tabs cannot reopen unless browsing history is preserved.
if you enable Clear history when LibreWolf closes
, but click Settings
and uncheck Browsing & download history
(everything else should be ok), then it should clear cookies but keep history (whats in CTRL+H menu). i also have 'Delete cookies and site data when LibreWolf is closed' enabled.
it is confusing how the options are layed out...