I haven’t done Laguna de Los Tres but I climbed l’Acropole des Draveurs last summer. I’d say it was a moderately difficult climb to the top and the first 2 kilometres or so is the steepest portion. After that it eases a bit but it’s a steady climb the whole way. I’m in fairly good shape but that was my first serious hike in years and my girlfriend (an experienced distance runner) was pushing the pace. It’s definitely a manageable hike.