I have no clear idea of what you can do with 50k, I spent 20k, but my plot is also very small. For the money, I initially set practically the same priorities as my predecessors: driveway (60 m²), splash protection strip around the house (46 m), entrance podium, terrace (30 m²), wall for retaining the slope (1 m high, 15 m long). Everything is made of dark granite for me; if there is money for it, I would do it again and again. From the remaining money, topsoil could still be delivered and spread, and then I planted the hedge myself.
Trees on the property are definitely a must-have at this size. For our [Handtuch], it had to be a slim shape, so we planted a columnar oak (Quercus robur Fastigiata) and a columnar beech – costing a reasonable size (for me from 3 m height) about 1,000 euros.
If you really have to set priorities: driveway, splash protection, a terrace, and everything to do with concrete should be done right away. Lighting and irrigation afterward. Fill up topsoil, plant a tree, and sow/lay lawn as well. I would wait with the rest of the planting and hedge. Let it sink in for a bit first.