Vector mechanics, and statics using physics

Hello everyone, I want to create a simulator for vectorial and static physics where users can build truss links for bridges or frameworks in a three-dimensional style, similar to Poly Bridge. I understand that I should use joints, but they seem to be unstable for my purpose. Additionally, when creating complex structures, the performance is very poor. I would appreciate it if someone could provide guidance on where I should look or what direction I should take.
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I know the math but I don’t know how to implement it in Unity. Additionally, I would like to omit collisions, because I only need to calculate the loads (tension, compression, torsion) on each element. I imagine that will improve performance but I don’t know how.
I add that I want the simulation to be with many hundreds of elements so performance is very important.

You can treat the beams as simple springs, connecting nodes with some mass. This omits any collision detection/resolution and is easily parallelizable using Jobs/Burst.