This is going to help for your research.

Probably worth having https://youtube.com/@thang010146 here. Hundreds, if not thousands, of animated mechanisms.

Related: I've posted similarly recently, but I wanted to share again how much improved I've recently found FreeCAD. I'm self-taught with CAD, and have repeatedly tried and discarded FreeCAD for several years. I've frequently recommended against FreeCAD here and elsewhere based on my bad experienced.

However, after finding a video [0] in which someone successfully --and without difficulty-- passed a Solidworks professional certification using FreeCAD, I gave it another go.

I've since been trialling FreeCAD via the 'bleeding edge' weekly development builds [1]. It's not perfect, and some functions are still very unintuitive, but within boundaries, it's now super-usable for relatively complex hobbyist-level CAD. In some areas, it's actually better than the competition I've tried, IMO - for example making and cutting threads.

[0] https://www.youtube.com/watch?v=VEfNRST_3x8

[1] https://github.com/FreeCAD/FreeCAD/releases