have a look at what egui creator (and his team) been doing with rerun [0]
Egui seems well suited to render even tens of thousands pointcloud with wgpu backend.
Rerun dev here :). Yes, we're using egui with its wgpu backend! As someone else pointed out it is backend agnostic - it essentially generates triangles & textures in GPU friendly way and passes those down to a backend implementation.
All the visualizations like the 3D scenes with point clouds etc. are rendered with our open-source in-house renderer ("re_renderer") which itself is then passing wgpu surfaces/commands to the egui wgpu backend that composites everything together then.
I use egui. The library itself is agnostic but relies on backend libraries for rendering, all of which (or at least the official ones) render on the GPU.