grass VS godot-jolt

https://grass.osgeo.org/

    GRASS GIS offers powerful raster, vector, and geospatial processing engines in a single integrated software suite. It includes tools for terrain and ecosystem modeling, hydrology, visualization of raster and vector data, management and analysis of geospatial data, and the processing of satellite and aerial imagery. It comes with a temporal framework for advanced time series processing and a Python API for rapid geospatial programming. GRASS GIS has been optimized for performance and large geospatial data analysis.

We haven't looked at integrating GRASS yet, as we're more interested in data display, not deep analysis. Just another example of a C/C++ library with front end bindings for Python. Numbers are crunched in C/C++, results returned to Python.

Anyone have good advice for where to learn how to use GRASS

Access: GRASS GIS

Some other Rust game engines ship with their own physics engine. Fyrox, for example, has advanced 2D/3D physics, supporting rigid bodies, joints, ray casting and more. Godot too, which has community-led Rust bindings also has an in-built physics engine as well as a Godot-native extension using the Jolt physics engine. In fact, which is reported to be more performant than the official physics engine.

When the performance of Godot's physics engine has been mentioned before I've seen https://github.com/godot-jolt/godot-jolt pointed to as a drop in more performant solution.

Haven't tried it in a project yet myself

No idea if this will solve your problems, but with Godot 4 Physics being a bit undercooked you might want to try a different physics engine. Like Godot-Jolt: https://github.com/godot-jolt/godot-jolt

Godot 4 itself is actually fairly good about diving to its C/C++ base for the nasty stuff. Like its Physics. The reimplementation for Jolt physics into Godot 4 is again C/C++ calculation library.

If you'd like to try out Godot Jolt for yourself, you can find the latest release, as well as important gotchas, on the project's GitHub page. Just bear in mind that the extension is still in development and will likely have a couple of bugs that have yet to be found. C# support for GDExtension is also not in a great place right now, so there are some issues there as well.

Try a different physics engine: https://github.com/godot-jolt/godot-jolt

Your comment made me do a bit of research and I found this: https://github.com/godot-jolt/godot-jolt

It's possible to create a GDExtension for it (similar to what was done for Jolt), but I haven't seen any for Bullet yet. There's a lot of hype going around Jolt, so it's understandably where most of the community effort is going :)

Or godot-jolt (linked in that Tweeter thread respones).