Most of what you describe can be accomplished with diesel Jet-A engines. These used to be unthinkable for GA because they were too heavy, but clean-sheet designs are making it possible.

Much easier to fuel, no electrical system dependencies, no spark plugs to foul, liquid cooling to keep the temps more constant, and dual redundant FADECs. Plus much better range.

But they're still expensive.

https://www.flyingmag.com/inside-aviation-diesel-revolution/