Pom, I think you’re underestimating the impact of the real ground on the vertical radiation pattern of any antenna. Any antenna significantly less than 2 wavelengths above ground will have an elevation angle significantly greater than 0 degrees.
This also applies to vertical antennas.
Here is an example of an optimal ground plane antenna for 20m with the feed point 10m above ground. This is certainly not easy to implement at a summit.
The first two images show the simulation in free space. The result shows the desired elevation angle of 0 degrees.
Then with real radiation pattern of the groundplane still 10m above ground!
Free space
Real underground
73 Chrisq