all that is only brain-rot statements with no technical meaning. lemme make this completly clear

mf= mass of feather mb= mass of ball me= mass of earth ae=accelaration of earth fg=force experienced by both

now in case of feather

force on earth is what? yes thats fg =G.mf.me/r^2

now thats the net force on earth, now what is newtons law? me.ae=G.mf.me/r^2

we get ae=G.mf/r^2

similarly in case of ball ae=G.mb/r^2

and accelaration of earth is clearly more in case of ball, and yes this is accelaration in non inertial frame study newtons laws of motion again if you didnt know, so your second paragraph is utter nonsense

instead of nonsense brainrot statements like 'Multiplication is associative, you can switch the masses around as you please, nowhere in the formula does it say “the greater mass” or “the smaller mass” you could just as well re-arrange the formula and come up with “earth moves with gm1/M” tell me where in equations you think i am wrong