I've been using Defraggler for many years, however now that almost all drives are SSD we desperatly need Need "Shutdown after Otimisation" not just Need "Shutdown after Defrag". I wish I could go to bed knowing my Win 10 PC would not be running all night asfter spending a couple of hours optimising my 8GB SSD's.
Personally I would not use Defraggler to optimise an SSD.
(Defraggler appears to be doing a zero fill - which is not needed on SSDs and is what will be taking the time).
Use the Windows built in 'Defragment and Optimise Drives' tool which will TRIM the drive, it will take seconds not hours - even with a 8TB SSD (I assume the 8GB was a typo).
You can schedule it to run daily, weekly, or monthly and then forget about it.
(I do it myself once a week, but have the schedules set too just in case I forget).
I do still have Defraggler but only use it on HDDs.