The real distinction
The piece frames it well: positionism (as critiqued) leans on automations and rehearsed patterns, coaches designing the solutions and players executing them; relationism prioritizes players reading and adapting to the ever-changing game and solving it themselves. The killer example — if you've rehearsed everything for a 4-4-2 press and the opponent shows up in a back three, the over-programmed team doesn't know what to do because the answers all came from the sideline.
Where I land
I want self-regulating players — that's the whole job for me. Not players who look to me for the answer, but players who read the situation and choose. So my instinct leans relationist: give them principles and the freedom to solve it. But I'd also say there's no single right way, and structure has real value; the best environments I've seen give players a clear framework AND the freedom to break it when the game asks. It's not either-or. It's how much of each, for these players, at this stage.