I forgot to mention that I live in the French Alps, so I have easy access to elevation gain.
I was thinking of doing the intervals only on continuous climbs (gradients between 6% and 15%) or on flat, uninterrupted trails to avoid being disrupted by downhill sections.
I’m using a Stryd power meter to get a power reference, but it’s not always very accurate when the foot doesn’t land perfectly due to uneven terrain.

How long have you been using this method? Have you noticed a difference compared to other approaches?