Most filament based printed frames end up with really nasty resonance; it’s possible to engineer damping around the issue with some clever 3D design if the parameters of the prints are measured, but overall 3D printing copter frames doesn’t tend to be a straightforward solution.

I wish we had some standard filament testing that most manufacturers were willing to provide results for.

Until that happens, this guy here is probably the next best thing: https://www.youtube.com/@MyTechFun

Plot twist: many of the "special" filaments aren't special at all or at least very exaggerated.

Yes. And when your design is simply beautiful as this is:

https://karolina.mgdubiel.com/drone/drone-img/05-30-26/cnc_c...

I agree with your first point.

The milled fiberglass the author used is a much better UAS frame material than anything from a filament 3d printer due to stiffness and related considerations.