yes, technique is very different and without proper training, is quite tiring. Had once tried brisk walking at 8-9min/km for more than 10km, felt worse than jogging at around same pace.
Definitely worse than jogging same pace, you can easily see this from the HR stats (also reflects on the energy expended). From another angle as in distance pov, you walk 5K is maciam like you run 8K.
The first time i tried running, it was 2 laps x 800m at my place (1.6K). I timed it on my phone, it was approx 6 mins 10 seconds (3.51 pace). Have not even purchased my watch then. heh......
That was in Nov 2022.
In many ways, i believe the walking trained my running. It's also a form of cross training if you look at it from another angle. (coz there are some articles stating these cycling, walking and stuff don't / cannot carry over)
edit - ok, gotta state that i also did 60-80 metres SIT also, so the neuro stimulus among other things are there. I do with my kid one, quite a few years already.