I assumed that .pub files could be openend and edited with LibreOffice. LIbreOffice hangs or goes dead and just never responds. So you have to Force close LibreOffice. Oh, wait a minute…after force closing LibreOffice and about 5 minutes has passed - the file opened! So my question is answered in a way. But, obviously, it is not or should not be recommended to use LibreOffice for MS Publisher files because this is not acceptable that a file takes 5 minutes to open? Can you possibly give any updated advice here? The last questions were asked in 2015. It is now 2019?
it is not or should not be recommended to use LibreOffice for MS Publisher files because this is not acceptable that a file takes 5 minutes to open
… so someone (who?) should not recommend (to who?) using a software to open files that might be opened by that software, when one needs them opened (e.g., not having other compatible software), because someone (you) found it too slow for your needs, based on unspecified sample, without a bug report providing a test case?