I've been trying a lot of playing about with LibreOffice Writer and I seem to be
almost there with what you want. So I'll give you what I've got so far and leave you to see if there's any way to get it perfect.
My approach has been to try to replace a full stop with a full stop and a line break. I can get a full stop replaced by a line break but only when losing the full stop from the resultant text. It's all to do with 'regular expressions', so you'll need this page of info:
https://help.libreoffice.org/Common/List_of_Regular_Expressions
To get as far as I've got up until now, start by pressing Ctrl and H together, to bring up the 'search & replace' dialogue box.
Under 'Other options', place a tick next to 'Regular expressions'.
In the 'Find' field, type \.[:space:]
In the 'Replace' field, type \n
Click 'Replace all'.
As you'll see, that will get you very close to where you want to be but it needs a bit more work to finish the job off properly. I'll leave you to see if there's any way that it can be done!