We appreciated the thought, but she would bring so many toys for our daughter it was overwhelming and we didn’t Have that much space.
It was clearly more for my mom than for us, she just likes to give.
So I reciprocated by saying thanks and promptly throwing/donating something older. This allowed my mom to keep giving and us to not have the clutter.
I’m glad to confirm what I already knew by your story. It would have hurt her and damaged our relationship if I would have asked her to stop.