Thanks @Superku, sounds good, but didn't hit my goal.

Another example:

I try to model procedural meshes (a rock or whatever) with Perlin Noise for example. Then i want to have a gradual LOD:

1. Create Proc-Mesh at LOD-Level 1 with 1 Octave.
2. If User zoom-in, then select all Vertices visibily in frustrum and if a certain threshhold (no fixed thresh, rather dynamic) is reached, tesselate the selected Vertices with higher Octave.
3. If more zoom in then select this new vertices and tesselate them again and detesselate all vertices which are not in frustrum view.

What i try to reach is, that i have a dynamic LOD, depentend initial on procedural creation of meshes.
The same is with a terrain. if you stand on the terrain every patch which is farer away should have the lowest LOD, but with a gradual LOD smoothing if the pathes are nearer at the camera. The most examples i see and knew from Model-LOD are 3-5 Stages.

My idea comes from a Voxel Engine and the 1st chapter of GPU Gems 3. i'd like to realize this within 3DGS, but without geometry shader.

I hope you could follow my thoghts.