I'm probably not alone here in being a longtime Linux user who started using a Macbook after the Apple Silicon transition, late 2022.
On Windows and Linux, inserting an em-dash is a laborious alt-code process. But on MacOS with an Apple keyboard, the `option` key acts like a tertiary shift, so an `–` em dash is just <option><->.
I didn't start using em-dashes (typing -- is just second nature to me and I'm still on Linux most of the time) when I got a Macbook, but I imagine some people in my shoes did.
On Linux, you can set up a Compose key, after which an em-dash is compose, three hyphens (Macintosh: shift-option-hyphen), and an en-dash is compose, two hyphens, period (Macintosh: option-hyphen). Also, a left (resp. right) single (resp. double) quote is compose, less-than (resp. greater-than), typewriter single (resp. double) quote. That’s how I enter them.
You can also (alternatively or at the same time) set up a “Level 3 shift” aka “Alternate Characters Key” aka AltGr, which gets you quotes with one of the English International layouts or quotes as well as dashes with an English Macintosh layout.
Someone recently created some long list of my reddit comments using them as a farcical claim of having used ChatGPT to author many dozens of 2010 comments.