>>1029520 (OP)
You have to start with the programs you use.
If you are truly serious you have to follow these.
If you can't because of the nature of your job then there's no point.
>Transition into using FOSS backed software or services.
As far as I know the email side isn't going any better. Cock.li or other allegedly "anonymous" servers are infested with the glowers.
I can recommend using Mailpile to manage your emails on PC but if you use webmail I suggest you use Tutanota.
Office programs like MS office suite have replacements on linux but bear in mind that these might give you a bit of a learning curve but they're usable and being used by scientists and engineers too! Gotta avoid getting your latest patent sent through or or eaten by malware or stolen by some spying M$ employee right? They use Unix (open source) or GNU operating systems.
Now if you're comfortable with the apps and have no violent reactions whatsoever then that's the time to transition into Linux or BSD.
Get comfortable with it by doing the so-called distro hopping. Try out different flavors. Gnome, KDE, Ubuntu. Manjaro and Ubuntu is recommended for beginners.
>Avoid association
At this point you should stop using M$ services including online ones. Not even skype! IE? are you Chinese? Microsoft email? Hotmail? Okay I suspect you're either a Jap or some old school windows XP guy.
Association happens when you get into your "private mode" and then switch to "identity mode".
Private mode is the "you that you don't want to be spied"
Identity mode is "your public figure"
The two will mix if you do access them simultaneously. 3rd party Cookies or Javascript, facebook.net or google syndication meant to carefully track you, FaceID for pictures or your Skype photoshots or even webcam, non-privacy respecting mail servers and malicious phones, They're all designed to build you a metadata profile, an online profile you can imagine as 'creepy and impossible' but it happens now and it's only a matter of implementation costs which is CHEAP considering the worth of what they're getting.
Consider using browser with Umatrix and block 3rd party cookies.
If you also use your "private mode" and "identity mode" with similar IP address with your name on the ISP registration that's also a vector for association especially since you live in the Land of Free.