Yeah it really doesn’t cross people’s minds how much data that they are freely giving away. I must admit that I have lapsed a bit with the encryption and connection I will use as I had deliberate reason to hide in the past.
It’s probably overkill for most but I would use a Linux OS called Tails that was a whole Tor based operating system that booted from a CD so that the system couldn’t be edited by outside sources. It’s still available as far as I know and is probably much faster now but if you want to go off the grid use a cheap bare bones laptop (as it boots from CD a big HDD is pointless) and burn the OS and use WiFi that isn’t paid for by you!
I had a cash only mobile phone running android with Tor and used an email service that annoyingly I have forgotten the name of but it was invite only with what I think was called PGP encryption built in (that was a nightmare to figure out how to use back then!)
Like I said I have been less severe with my encryption these days and I have forgotten most of the methods used as it was an ordeal to even send an email back then but I guess things have been made more accessible now but I always have a version of Tor on my devices just incase but I would recommend something like Tails OS for the ultimate protection… No USB sticks or HDDs either! Use a CD or DVD and you can’t get any malware!