I installed Bleachbit in dom0 but haven’t run it yet.
I would like to double-erase the free space and also delete as many logs as possible.
Is running Bleachbit in dom0 going to make the system unbootable?
Dom0 doesn’t run any software, and it’s unsafe to install and run anything there:
Actually, dom0 is the right place if you want to run program to affect your physical storage (which is what bleachbit is doing). Good idea or not 
Bleachbit works fine in dom0. Have it installed ATM and
ran it many times.
Does not affect system booting.