Congrats! That's an impressive number of years to stay on keto.

i recently started dating someone who's been on keto for 20+ years

I didn't even remember it was that old (researched it a lot before I started, but mainly focused on studies about the effects and issues, not history, plus, well, 10 years ago). Must have been hard on the early days without easily available nut flours and tons of recipes online.

she likes doing difficult things. she's pretty amazing actually

it turns out it's more than a century old; see https://en.wikipedia.org/wiki/Ketogenic_diet#Diet

what were the most important practices for you getting started on keto

Not living in the US where there's a ton of added sugar in things that don't need added sugar.

Though now the disadvantage is that things like low carb wraps are not a normal store item, and neither monkfruit not alluose are allowed as food in the EU.

But I guess by far the biggest part was actually that I've been working from home since 2008 and love cooking ;)