Preheat oven to 425F, grill to medium high. Put all ingredients for vegetables on large sheet pan lined with parchment. Mix together with your hands until sauce is distributed evenly. Give vegetables space to caramelize by placing in a single layer with as much of the cut sides directly on the pan as possible.
Roast vegetables in oven for about 15 minutes. Pull them out, flip them to get the char on other sides. Return to oven for another 10-15 minutes until fork tender and deeply colored.
On preheated grill, put heavily seasoned ribeye down, leaving it untouched for about 4-6 minutes. Flip and cook for another 4-6 minutes until desired doneness is achieved. For food safety, make sure it's at least 145F. Rest for 5-10 minutes before slicing thinly on the bias.
While vegetables are roasting make the harissa mayonnaise by mixing all ingredients together. Set aside.
Mix all chimichurri ingredients together. Set aside.
To plate, put a dollop of harissa mayonnaise on plate. Fan out thinly sliced ribeye in a starburst pattern. Top with a few large spoonfuls of vegetables. Divide feta crumbles between two plates. Drizzle remaining harissa mayonnaise on top. Dot with chimichurri. ENJOY!