@_elena thank you for this thread. Having had a few high-popularity toots myself, this matches my experience well.
When my follower count reached a certain level I've noticed that when I respond in a thread, especially a thread that happens to be controversial and polarizing, that might bring a bunch other people to also reply – potentially leading to a pile-on of sorts.
So I switched my default post visibility to "Quiet public". That helped a lot, and felt like the responsible thing to do.