Even if you imagine doing them separately, the acceleration of the Earth cannot be calculated based on just a singular force unless you assume nothing else is exerting a force on the Earth during the process of the fall. For a realistic model, this is a bad assumption. The Earth is a massive system which interacts with a lot of different systems. The one tiny force exerted on it by either the feather or bowling ball has no measurable effect on the motion of Earth. This is not just a mass issue, it's the fact that Earth's free body diagram would be full of Force Vectors and only one of them would either be the feather or bowling ball as they fall.
As for my second point, I understand your model and I am defining these references frames by talking about where an observer is located. An observer standing still on Earth would measure the acceleration of the feather or bowling ball to be 9.81 m/s/s. If we placed a camera on the feather or bowling ball during the fall, then it would also measure the acceleration of the Earth to be 9.81 m/s/s. There is no classical way that these two observers would disagree with each other in the magnitudes of the acceleration.
Think of a simpler example. A person driving a car towards someone standing at a stop sign. If the car is moving 20 mph towards the pedestrian, then in the perspective of the car's driver, the pedestrian is moving 20 mph towards them. There is no classical way that these two speeds will be different.
Okay, this notion is just incorrect. Harris, during her time as senator, was one of the most left leaning senators out of all Democrats. Her votes almost completely aligned with Bernie Sanders.
Was misogyny THE reason Harris loss, probably not; but it definitely played a meaningful role. During the campaign race, there were a lot of information being pushed to American citizens. It was up to us to process the information and choose what to believe and what to throw away. Post-election, we are learning that people were judging Harris based on false premises. Americans were willing to believe a lot of bullshit about Harris, whereas Trump got the opposite treatment: Americans willingfully ignored terrible truths about Trump. I think misogyny played a role in defining this difference in how we treated information regarding each candidates.