the save icon on tool bar no longer works - can s"save as" but nit by clicking on the icon with a redspot.
Are you on Windows and use AVG or Avast anti-virus? Read their instructions on how to add LibreOffice to the Allowed list. You might have specify soffice.bin ( see Defender Controlled folder access exception for LibreOffice - The Document Foundation Wiki) but I think when I looked at their instructions a few years ago you could select LibreOffice from the list OK.
If not then please add details
I have recently encountered this problem with LO Calc ver 25.8.3.2 (x86_64) running on Fedora 43. Ctrl+S works, so until this is fixed, that is my workaround.