Another thing you can try is to update your OS from Windows 8 to Windows 10 if your machine is compatible. Windows 8 is nowhere near as stable as Windows 10.
Neither the OS nor the number of Word instances is likely to be at all relevant.
__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]
06-03-2021, 03:01 PM
Word "choking"
Windows 10 
Office 2016
Threaded Mode