You can tighten the fidelity with smaller voxels and marching cubes to make it more realistic but you’re likely overestimating the computer power of modern hardware if you want higher levels of control and fidelity than voxels will offer. In the most optimistic light, if you need full destructible terrain in the vein of minecraft, you’re looking at lots of focused and custom and complicated work. The solution I offered is more in line with a beginner. There are other approaches, but none nearly as accessible as voxels for a newcomer.
A more controlled less technically complex narrative based game would be much easier as a learning experience, though you will still have to reign in your scope. This will save you lots of abandoned projects over the years. Basically any genre you can find full tutorials for is a solid bet, as if you ever get stuck you can check how other implementations are done.