Will it work if you set every 4 days to auto restart? It is not important, I suppose, to restart same day always. But same exact hour sounds nice to have like it is now.
English is not my native language so allow me to give you an example of my suggestion :
Monday 15:00 + 4 days = Friday 15:00 + 4 days = Tuesday 15:00 + 4 days = Saturday 15:00 . . .
Thank you in advance.