Things I do when I get a new Mac, more or less in order:

• install Homebrew
• use Homebrew to install pandoc
• install BBedit
• install MacTex
• type this into the terminal: defaults write com.barebones.bbedit FullScreenWindowsHogScreen -bool NO
• type this into the terminal: defaults write com.apple.dock single-app -bool true (followed by killall Dock)
• enable Night Shift
• install TextExpander
• install Alfred
• install Hazeover
• install Hazel

Everything else can wait; once I have the above in place — plus of course syncing all my existing TextExpander snippets — I can do almost everything I really need to do on a computer, with maximum focus and speed.