might want to use d0wn or opennic instead.
Over-reaction imo but what os are you using?
Delete metadata from the spreadsheets. Use a virtualmachine vmwware or virtualbox and load windows inside that so that they can brick the virtual machine not the os itself. also windows and mac android ios all bent over. Systemd linux supposedly comped aswell.
are you using a the free google dns as a resolver? if so that is no better than your isp's dns. So the advantage is essentially a modicum of privacy.
I have had that happen i think its a coincidence. Did you run an update or upgrade recently? that sounds suspicious though not gonna lie.
actually i have fucked up the grub with upgrades but never had a guest account auto-login. I would backup files and maybe post info in a vm.
No idea without speculating. I just knew some open-source alternatives.
It literally is supposed to be really secure. was listed in a list with https://libertybsd.net/ as secure os's. I look at it the same way the dragon nsa program its a tool that clearly can be used but i understand the hesitation. Consider systemd-free alternatives to fucking ubuntu though. Tens is clearly more secure than ubuntu.
of course..