Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper.
Wash and dice the potato into small 1/2-inch cubes to ensure they cook at the same rate as the other vegetables.
Slice the zucchini into half-moons, chop the celery into thin crescents, and leave the cherry tomatoes whole.
Place the diced potatoes, zucchini, celery, and cherry tomatoes onto the prepared sheet pan.
Add the vegan gyro strips to the pan, breaking up any large clumps.
Drizzle the olive oil over the ingredients and sprinkle evenly with dried oregano, garlic powder, sea salt, and black pepper.
Toss everything thoroughly with your hands or tongs until well-coated, then spread into a single, even layer.
Roast for 20 to 25 minutes, tossing halfway through, until the potatoes are fork-tender and the gyro meat is slightly crisped and golden.
Remove from the oven and immediately drizzle with fresh lemon juice to brighten the savory flavors before serving.