You know what, you do what you can. It is unrealistic to believe you can avoid every entity that is morally offensive.
I have participated in boycotts in the past, always writing a letter to the company letting them know why I was leaving/not buying, etc. Typically I have focused on local companies I can influence, but I did boycott Target until they changed their giving policies and I also boycotted American Girl (my niece has some) until they disassociated with a pro-abortion organization.
You do not “need” to change banks. It is your decision. You could certainly write to them and voice your opinion that they should not give to PP.