Hands down, Blender. See Ian Hubert’s channel[0] for samples of what can be achieved with Blender by a tiny team.
His examples tend to be specific to VFX, but Blender is quite general-purpose as far as motion design goes with an NLE, support for the familiar “expressions” paradigm, and so on.
I use Blender and Ian Hubert’s recent work is what got me into it. It’s an excellent tool when it comes to the kind of motion-tracked work he does (and which I hope to get into) but for quickly cutting together motion graphics I have not found it to be as handy.
His examples tend to be specific to VFX, but Blender is quite general-purpose as far as motion design goes with an NLE, support for the familiar “expressions” paradigm, and so on.
[0] https://www.youtube.com/watch?v=RxD6H3ri8RI