Are all zone 2s the same?

No, and it isn't close. The same run can be zone 2 or zone 3 depending on which method your app uses and whether anyone ever told it your real max. Put your numbers in and watch the boundary move.

Two methods, two different answers

Flip the method toggle above and watch zone 2 move. Percentage of max ignores your resting heart rate entirely; Karvonen draws the bands across your reserve, so a low resting heart rate pushes every boundary up. For me that's the difference between a zone 2 ceiling around 143 and one around 156, and thirteen beats is the whole gap between an easy run and a moderately hard one.

Neither is right. They're both lines drawn across a continuum, and the physiological version - the one from a lab test with a lactate meter - usually sits somewhere else again. Which is why the talk test outranks all of them: if you can hold a conversation you're in zone 2, whatever your watch has decided.

Some people just rev high

I'm in my early thirties and my heart rate goes from 43 asleep to 205 running. That's a 162 bpm spread, and the first time I looked at a chart telling me my max should be about 188 I assumed something was broken, either the strap or me, and as far as I can tell it was neither. Some people just rev high, and the 220-minus-age thing is a population average with a standard deviation of roughly 10–12 bpm around it, so being twenty off is unremarkable.

So the person running next to you at the same pace might be at 120 while you're at 165 and that comparison doesn't mean much, what matters is knowing your own max and resting numbers and making every app you use agree with them. If Strava and your watch are still on 220-minus-age they'll spend the next year calling every easy run a tempo.

Don't take a max HR off a calculator. Take it off the highest number you've actually seen on a chest strap during a hard finish - wrist optical sensors undercount badly at the top end, which is its own way of getting your zones wrong.