Then maybe go for something like an escape-the-room game perhaps (or escape-the-mansion if you want to go a bit bigger). Keeps the scale under control, mainly relies on the quality of the art/assets, level and puzzle design, offers relatively simple programming challenges but everything can be done with Blueprints alone. The overall theme can go anywhere, whether you want to go for scary, mysterious, whimsical, abstract, surreal or anything in between. Aaaaand it’s definitely doable in a one-year timeframe.